diff --git a/icu4c/source/data/locales/ar.txt b/icu4c/source/data/locales/ar.txt
index aafe88a..af41175 100644
--- a/icu4c/source/data/locales/ar.txt
+++ b/icu4c/source/data/locales/ar.txt
@@ -1634,6 +1634,7 @@
                     "تيشو",
                     "شووا",
                     "هيسي",
+                    "ريوا",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/ast.txt b/icu4c/source/data/locales/ast.txt
index d9d5d1e..355dced 100644
--- a/icu4c/source/data/locales/ast.txt
+++ b/icu4c/source/data/locales/ast.txt
@@ -2304,6 +2304,7 @@
                     "Taishō",
                     "e. Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
                 narrow{
                     "Taika",
@@ -2542,6 +2543,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide{
                     "Taika (645–650)",
@@ -2780,6 +2782,7 @@
                     "Taishō",
                     "era Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
             intervalFormats{
diff --git a/icu4c/source/data/locales/bs_Cyrl.txt b/icu4c/source/data/locales/bs_Cyrl.txt
index 1c6eeb3..7d2533c 100644
--- a/icu4c/source/data/locales/bs_Cyrl.txt
+++ b/icu4c/source/data/locales/bs_Cyrl.txt
@@ -1030,6 +1030,7 @@
                     "Таишо",
                     "Шова",
                     "Хаисеи",
+                    "Реива",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/cs.txt b/icu4c/source/data/locales/cs.txt
index 6fc8684..08b3df4 100644
--- a/icu4c/source/data/locales/cs.txt
+++ b/icu4c/source/data/locales/cs.txt
@@ -3697,6 +3697,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
                 narrow{
                     "Taika (645–650)",
@@ -3935,6 +3936,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide{
                     "Taika (645–650)",
@@ -4173,6 +4175,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
             intervalFormats{
diff --git a/icu4c/source/data/locales/de.txt b/icu4c/source/data/locales/de.txt
index efd2206..1e12628 100644
--- a/icu4c/source/data/locales/de.txt
+++ b/icu4c/source/data/locales/de.txt
@@ -1601,6 +1601,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/he.txt b/icu4c/source/data/locales/he.txt
index 427dd79..8d5961a 100644
--- a/icu4c/source/data/locales/he.txt
+++ b/icu4c/source/data/locales/he.txt
@@ -1837,6 +1837,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/hi.txt b/icu4c/source/data/locales/hi.txt
index 9af2861..f40f952 100644
--- a/icu4c/source/data/locales/hi.txt
+++ b/icu4c/source/data/locales/hi.txt
@@ -1239,6 +1239,7 @@
                     "ताईशो",
                     "शोवा",
                     "हेईसेई",
+                    "रेइवा",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/hr.txt b/icu4c/source/data/locales/hr.txt
index 34322a8..044901e 100644
--- a/icu4c/source/data/locales/hr.txt
+++ b/icu4c/source/data/locales/hr.txt
@@ -1567,6 +1567,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/id.txt b/icu4c/source/data/locales/id.txt
index ac9eb42..9bc40be 100644
--- a/icu4c/source/data/locales/id.txt
+++ b/icu4c/source/data/locales/id.txt
@@ -2217,6 +2217,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/ja.txt b/icu4c/source/data/locales/ja.txt
index ab8c0ab..59a8849 100644
--- a/icu4c/source/data/locales/ja.txt
+++ b/icu4c/source/data/locales/ja.txt
@@ -2464,6 +2464,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
                 narrow{
                     "大化",
@@ -2702,6 +2703,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/ko.txt b/icu4c/source/data/locales/ko.txt
index df9f96e..98234a8 100644
--- a/icu4c/source/data/locales/ko.txt
+++ b/icu4c/source/data/locales/ko.txt
@@ -1909,6 +1909,7 @@
                     "다이쇼",
                     "쇼와",
                     "헤이세이",
+                    "레이와",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/lo.txt b/icu4c/source/data/locales/lo.txt
index cf70906..5f34d1a 100644
--- a/icu4c/source/data/locales/lo.txt
+++ b/icu4c/source/data/locales/lo.txt
@@ -1845,6 +1845,7 @@
                     "ໄຕໂຊ",
                     "ໂຊວາ",
                     "ຮີຊີ",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/lt.txt b/icu4c/source/data/locales/lt.txt
index 88f50bf..2846048 100644
--- a/icu4c/source/data/locales/lt.txt
+++ b/icu4c/source/data/locales/lt.txt
@@ -2466,6 +2466,7 @@
                     "Taišo",
                     "Šova",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/nb.txt b/icu4c/source/data/locales/nb.txt
index d3a0037..3a20f9b 100644
--- a/icu4c/source/data/locales/nb.txt
+++ b/icu4c/source/data/locales/nb.txt
@@ -5483,6 +5483,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
                 narrow{
                     "Taika (645–650)",
@@ -5721,6 +5722,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide{
                     "Taika (645–650)",
@@ -5959,6 +5961,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
             intervalFormats{
diff --git a/icu4c/source/data/locales/nl.txt b/icu4c/source/data/locales/nl.txt
index 0430a50..378da5b 100644
--- a/icu4c/source/data/locales/nl.txt
+++ b/icu4c/source/data/locales/nl.txt
@@ -4894,6 +4894,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
                 narrow{
                     "Taika (645–650)",
@@ -5132,6 +5133,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide{
                     "Taika (645–650)",
@@ -5370,6 +5372,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/root.txt b/icu4c/source/data/locales/root.txt
index e419ce9..8dbbee1 100644
--- a/icu4c/source/data/locales/root.txt
+++ b/icu4c/source/data/locales/root.txt
@@ -1713,6 +1713,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
                 narrow{
                     "Taika (645–650)",
@@ -1951,6 +1952,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide:alias{"/LOCALE/calendar/japanese/eras/abbreviated"}
             }
diff --git a/icu4c/source/data/locales/ru.txt b/icu4c/source/data/locales/ru.txt
index 3fdd356..f2bbed9 100644
--- a/icu4c/source/data/locales/ru.txt
+++ b/icu4c/source/data/locales/ru.txt
@@ -1837,6 +1837,7 @@
                     "Эпоха Тайсьо",
                     "Сьова",
                     "Эпоха Хэйсэй",
+                    "Рэйва",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/sr.txt b/icu4c/source/data/locales/sr.txt
index 821d13a..860c491 100644
--- a/icu4c/source/data/locales/sr.txt
+++ b/icu4c/source/data/locales/sr.txt
@@ -1246,6 +1246,7 @@
                     "Таишо",
                     "Шова",
                     "Хаисеи",
+                    "Реива",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/sr_Latn.txt b/icu4c/source/data/locales/sr_Latn.txt
index 57a1279..8bcc68c 100644
--- a/icu4c/source/data/locales/sr_Latn.txt
+++ b/icu4c/source/data/locales/sr_Latn.txt
@@ -1247,6 +1247,7 @@
                     "Taišo",
                     "Šova",
                     "Haisei",
+                    "Reiva",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/sv.txt b/icu4c/source/data/locales/sv.txt
index 01debf9..beb77f4 100644
--- a/icu4c/source/data/locales/sv.txt
+++ b/icu4c/source/data/locales/sv.txt
@@ -1630,6 +1630,7 @@
                     "Taishō",
                     "Shōwa",
                     "Heisei",
+                    "Reiwa",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/th.txt b/icu4c/source/data/locales/th.txt
index 4794938..19add19 100644
--- a/icu4c/source/data/locales/th.txt
+++ b/icu4c/source/data/locales/th.txt
@@ -2332,6 +2332,7 @@
                     "ทะอิโช",
                     "โชวะ",
                     "เฮเซ",
+                    "เรวะ",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/yue.txt b/icu4c/source/data/locales/yue.txt
index 74dd462..8d14665 100644
--- a/icu4c/source/data/locales/yue.txt
+++ b/icu4c/source/data/locales/yue.txt
@@ -2394,6 +2394,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/yue_Hans.txt b/icu4c/source/data/locales/yue_Hans.txt
index b087983..97b6215 100644
--- a/icu4c/source/data/locales/yue_Hans.txt
+++ b/icu4c/source/data/locales/yue_Hans.txt
@@ -2392,6 +2392,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/zh.txt b/icu4c/source/data/locales/zh.txt
index 6e8013b..f1aeca4 100644
--- a/icu4c/source/data/locales/zh.txt
+++ b/icu4c/source/data/locales/zh.txt
@@ -3403,6 +3403,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
                 narrow{
                     "大化(645–650)",
@@ -3641,6 +3642,7 @@
                     "T",
                     "S",
                     "H",
+                    "R",
                 }
                 wide{
                     "大化 (645–650)",
@@ -3879,6 +3881,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
             }
         }
diff --git a/icu4c/source/data/locales/zh_Hant.txt b/icu4c/source/data/locales/zh_Hant.txt
index 5ff361e..f2a61ce 100644
--- a/icu4c/source/data/locales/zh_Hant.txt
+++ b/icu4c/source/data/locales/zh_Hant.txt
@@ -5737,6 +5737,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
                 narrow{
                     "大化",
@@ -5975,6 +5976,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
                 wide{
                     "大化",
@@ -6213,6 +6215,7 @@
                     "大正",
                     "昭和",
                     "平成",
+                    "令和",
                 }
             }
             intervalFormats{
diff --git a/icu4c/source/i18n/japancal.cpp b/icu4c/source/i18n/japancal.cpp
index 17b4e07..e00489a 100644
--- a/icu4c/source/i18n/japancal.cpp
+++ b/icu4c/source/i18n/japancal.cpp
@@ -276,7 +276,8 @@
     {  1868,    9,  8 },   // Meiji    232
     {  1912,    7, 30 },   // Taisho   233
     {  1926,   12, 25 },   // Showa    234
-    {  1989,    1,  8 }   // Heisei    235
+    {  1989,    1,  8 },   // Heisei   235
+    {  2019,    5,  1 }    // Reiwa    236
 };
 
 #define kEraCount UPRV_LENGTHOF(kEraInfo)
diff --git a/icu4c/source/test/intltest/incaltst.cpp b/icu4c/source/test/intltest/incaltst.cpp
index 1e79576..88c98b5 100644
--- a/icu4c/source/test/intltest/incaltst.cpp
+++ b/icu4c/source/test/intltest/incaltst.cpp
@@ -77,6 +77,7 @@
     CASE(7,TestPersian);
     CASE(8,TestPersianFormat);
     CASE(9,TestTaiwan);
+    CASE(10,TestJapaneseHeiseiToReiwa);
     default: name = ""; break;
     }
 }
@@ -626,23 +627,23 @@
         // Test simple parse/format with adopt
         UDate aDate = 0; 
         
-        // Test parse with missing era (should default to current era, heisei)
+        // Test parse with missing era (should default to current era)
         // Test parse with incomplete information
         logln("Testing parse w/ missing era...");
-        SimpleDateFormat *fmt = new SimpleDateFormat(UnicodeString("y.M.d"), Locale("ja_JP@calendar=japanese"), status);
+        SimpleDateFormat *fmt = new SimpleDateFormat(UnicodeString("y/M/d"), Locale("ja_JP@calendar=japanese"), status);
         CHECK(status, "creating date format instance");
         if(!fmt) { 
             errln("Couldn't create en_US instance");
         } else {
             UErrorCode s2 = U_ZERO_ERROR;
             cal2->clear();
-            UnicodeString samplestr("1.1.9");
+            UnicodeString samplestr("1/5/9");
             logln(UnicodeString() + "Test Year: " + samplestr);
             aDate = fmt->parse(samplestr, s2);
             ParsePosition pp=0;
             fmt->parse(samplestr, *cal2, pp);
-            CHECK(s2, "parsing the 1.1.9 string");
-            logln("*cal2 after 119 parse:");
+            CHECK(s2, "parsing the 1/5/9 string");
+            logln("*cal2 after 159 parse:");
             str.remove();
             fmt2->format(aDate, str);
             logln(UnicodeString() + "as Gregorian Calendar: " + str);
@@ -653,7 +654,7 @@
             int32_t expectYear = 1;
             int32_t expectEra = JapaneseCalendar::getCurrentEra();
             if((gotYear!=1) || (gotEra != expectEra)) {
-                errln(UnicodeString("parse "+samplestr+" of 'y.m.d' as Japanese Calendar, expected year ") + expectYear + 
+                errln(UnicodeString("parse "+samplestr+" of 'y/m/d' as Japanese Calendar, expected year ") + expectYear + 
                     UnicodeString(" and era ") + expectEra +", but got year " + gotYear + " and era " + gotEra + " (Gregorian:" + str +")");
             } else {            
                 logln(UnicodeString() + " year: " + gotYear + ", era: " + gotEra);
@@ -666,7 +667,7 @@
         // Test simple parse/format with adopt
         UDate aDate = 0; 
         
-        // Test parse with missing era (should default to current era, heisei)
+        // Test parse with missing era (should default to current era)
         // Test parse with incomplete information
         logln("Testing parse w/ just year...");
         SimpleDateFormat *fmt = new SimpleDateFormat(UnicodeString("y"), Locale("ja_JP@calendar=japanese"), status);
@@ -678,7 +679,7 @@
             cal2->clear();
             UnicodeString samplestr("1");
             logln(UnicodeString() + "Test Year: " + samplestr);
-            aDate = fmt->parse(samplestr, s2);
+            aDate = fmt->parse(samplestr, s2);  // Should be parsed as the first day of the current era
             ParsePosition pp=0;
             fmt->parse(samplestr, *cal2, pp);
             CHECK(s2, "parsing the 1 string");
@@ -691,7 +692,7 @@
             int32_t gotYear = cal2->get(UCAL_YEAR, s2);
             int32_t gotEra = cal2->get(UCAL_ERA, s2);
             int32_t expectYear = 1;
-            int32_t expectEra = 235; //JapaneseCalendar::kCurrentEra;
+            int32_t expectEra = JapaneseCalendar::getCurrentEra();
             if((gotYear!=1) || (gotEra != expectEra)) {
                 errln(UnicodeString("parse "+samplestr+" of 'y' as Japanese Calendar, expected year ") + expectYear + 
                     UnicodeString(" and era ") + expectEra +", but got year " + gotYear + " and era " + gotEra + " (Gregorian:" + str +")");
@@ -700,13 +701,47 @@
             }
             delete fmt;
         }
-    }    
+    }
 
     delete cal2;
     delete cal;
     delete fmt2;
 }
 
+void IntlCalendarTest::TestJapaneseHeiseiToReiwa() {
+    Calendar *cal;
+    UErrorCode status = U_ZERO_ERROR;
+    cal = Calendar::createInstance(status);
+    CHECK(status, UnicodeString("Creating default Gregorian Calendar"));
+    cal->set(2019, UCAL_APRIL, 29);
+
+    DateFormat *jfmt = DateFormat::createDateInstance(DateFormat::LONG, "ja@calendar=japanese");
+    CHECK(status, UnicodeString("Creating date format ja@calendar=japanese"))
+
+    const char* EXPECTED_FORMAT[4] = {
+        "\\u5E73\\u621031\\u5E744\\u670829\\u65E5", // Heisei 31 April 29
+        "\\u5E73\\u621031\\u5E744\\u670830\\u65E5", // Heisei 31 April 30
+        "\\u4EE4\\u548c1\\u5E745\\u67081\\u65E5",   // Reiwa 1 May 1
+        "\\u4EE4\\u548c1\\u5E745\\u67082\\u65E5"    // Reiwa 1 May 2
+    };
+
+    for (int32_t i = 0; i < 4; i++) {
+        UnicodeString dateStr;
+        UDate d = cal->getTime(status);
+        CHECK(status, UnicodeString("Get test date"));
+        jfmt->format(d, dateStr);
+        UnicodeString expected(UnicodeString(EXPECTED_FORMAT[i], -1, US_INV).unescape());
+        if (expected.compare(dateStr) != 0) {
+            errln(UnicodeString("Formatting year:") + cal->get(UCAL_YEAR, status) + " month:"
+                + cal->get(UCAL_MONTH, status) + " day:" + (cal->get(UCAL_DATE, status) + 1)
+                + " - expected: " + expected + " / actual: " + dateStr);
+        }
+        cal->add(UCAL_DATE, 1, status);
+        CHECK(status, UnicodeString("Add 1 day"));
+    }
+    delete jfmt;
+    delete cal;
+}
 
 
 
diff --git a/icu4c/source/test/intltest/incaltst.h b/icu4c/source/test/intltest/incaltst.h
index 628b6e4..52b121d 100644
--- a/icu4c/source/test/intltest/incaltst.h
+++ b/icu4c/source/test/intltest/incaltst.h
@@ -34,7 +34,8 @@
     void TestJapanese(void);
     void TestJapaneseFormat(void);
     void TestJapanese3860(void);
-    
+    void TestJapaneseHeiseiToReiwa(void);
+
     void TestPersian(void);
     void TestPersianFormat(void);
 
diff --git a/icu4c/source/test/testdata/format.txt b/icu4c/source/test/testdata/format.txt
index c0364e2..c598ade 100644
--- a/icu4c/source/test/testdata/format.txt
+++ b/icu4c/source/test/testdata/format.txt
@@ -494,35 +494,35 @@
                     "",
                     "PATTERN=G y",
                     "YEAR=8",
-                    "Heisei 8"
+                    "Reiwa 8"
                },
                {
                     "en_US@calendar=japanese",         
                     "",
                     "PATTERN=G yy",
                     "YEAR=8",
-                    "Heisei 08"
+                    "Reiwa 08"
                },
                {
                     "en_US@calendar=japanese",         
                     "",
                     "PATTERN=G yyy",
                     "YEAR=8",
-                    "Heisei 008"
+                    "Reiwa 008"
                },
                {
                     "en_US@calendar=japanese",         
                     "",
                     "PATTERN=G yyyy",
                     "YEAR=8",
-                    "Heisei 0008"
+                    "Reiwa 0008"
                },
                {
                     "en_US@calendar=japanese",         
                     "",
                     "PATTERN=G yyyyy",
                     "YEAR=8",
-                    "Heisei 00008"
+                    "Reiwa 00008"
                },
 
             }
diff --git a/icu4c/source/test/testdata/structLocale.txt b/icu4c/source/test/testdata/structLocale.txt
index bd3d2b9..e6372c3 100644
--- a/icu4c/source/test/testdata/structLocale.txt
+++ b/icu4c/source/test/testdata/structLocale.txt
@@ -25784,6 +25784,7 @@
                     "",
                     "",
                     "",
+                    "",
                 }
                 wide{
                     "",
@@ -26022,6 +26023,7 @@
                     "",
                     "",
                     "",
+                    "",
                 }
                 narrow{
                     "",
@@ -26260,6 +26262,7 @@
                     "",
                     "",
                     "",
+                    "",
                 }
             }
             intervalFormats{