diff --git a/src/lib/isISO8601.js b/src/lib/isISO8601.js
index 6eea9ae27..acf758000 100644
--- a/src/lib/isISO8601.js
+++ b/src/lib/isISO8601.js
@@ -2,9 +2,9 @@ import assertString from './util/assertString';
 
 /* eslint-disable max-len */
 // from http://goo.gl/0ejHHW
-const iso8601 = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;
+const iso8601 = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|(?:\+(?:(?:0\d|1[0-3]):?[0-5]\d|14:?00|(?:0\d|1[0-4]))|-(?:(?:0\d|1[01]):?[0-5]\d|12:?00|(?:0\d|1[0-2]))))?)?)?$/;
 // same as above, except with a strict 'T' separator between date and time
-const iso8601StrictSeparator = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;
+const iso8601StrictSeparator = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|(?:\+(?:(?:0\d|1[0-3]):?[0-5]\d|14:?00|(?:0\d|1[0-4]))|-(?:(?:0\d|1[01]):?[0-5]\d|12:?00|(?:0\d|1[0-2]))))?)?)?$/;
 /* eslint-enable max-len */
 const isValidDate = (str) => {
   // str must have passed the ISO8601 check
diff --git a/test/validators.test.js b/test/validators.test.js
index cdde41a07..0cc9d983b 100644
--- a/test/validators.test.js
+++ b/test/validators.test.js
@@ -12359,6 +12359,12 @@ describe('Validators', () => {
     '2009-05-19 14:39:22-06:00',
     '2009-05-19 14:39:22+0600',
     '2009-05-19 14:39:22-01',
+    '2009-05-19 14:39:22+14:00',
+    '2009-05-19 14:39:22+1400',
+    '2009-05-19 14:39:22+14',
+    '2009-05-19 14:39:22-12:00',
+    '2009-05-19 14:39:22-1200',
+    '2009-05-19 14:39:22-12',
     '20090621T0545Z',
     '2007-04-06T00:00',
     '2007-04-05T24:00',
@@ -12405,6 +12411,14 @@ describe('Validators', () => {
     '2010-13-1',
     'nonsense2021-01-01T00:00:00Z',
     '2021-01-01T00:00:00Znonsense',
+    '2009-05-19 14:39:22+14:01',
+    '2009-05-19 14:39:22+15:00',
+    '2009-05-19 14:39:22+1500',
+    '2009-05-19 14:39:22+15',
+    '2009-05-19 14:39:22-12:01',
+    '2009-05-19 14:39:22-13:00',
+    '2009-05-19 14:39:22-1300',
+    '2009-05-19 14:39:22-13',
     '2009-W00',
     '2009-W00-1',
     '2024-W00',
@@ -12477,6 +12491,12 @@ describe('Validators', () => {
         '2009W511',
         '2009-05-19',
         '2009-05-19T14:39Z',
+        '2009-05-19T14:39:22+14:00',
+        '2009-05-19T14:39:22+1400',
+        '2009-05-19T14:39:22+14',
+        '2009-05-19T14:39:22-12:00',
+        '2009-05-19T14:39:22-1200',
+        '2009-05-19T14:39:22-12',
         '2009-W21-2',
         '2009-W21-2T01:22',
         '2009-139',
@@ -12520,6 +12540,14 @@ describe('Validators', () => {
         '2010-02-18T16:23.33.600',
         '2010-02-18T16,25:23:48,444',
         '2010-13-1',
+        '2009-05-19T14:39:22+14:01',
+        '2009-05-19T14:39:22+15:00',
+        '2009-05-19T14:39:22+1500',
+        '2009-05-19T14:39:22+15',
+        '2009-05-19T14:39:22-12:01',
+        '2009-05-19T14:39:22-13:00',
+        '2009-05-19T14:39:22-1300',
+        '2009-05-19T14:39:22-13',
         '2009-05-19 00:00',
         // Previously valid cases
         '2009-05-19 14',