diff --git a/src/formats.ts b/src/formats.ts
index d3cde9b..ec8c9cb 100644
--- a/src/formats.ts
+++ b/src/formats.ts
@@ -47,9 +47,9 @@ export const fullFormats: DefinedFormats = {
   date: fmtDef(date, compareDate),
   // date-time: http://tools.ietf.org/html/rfc3339#section-5.6
   time: fmtDef(getTime(true), compareTime),
-  "date-time": fmtDef(getDateTime(true), compareDateTime),
+  "date-time": fmtDef(getDateTime(), compareDateTime),
   "iso-time": fmtDef(getTime(), compareIsoTime),
-  "iso-date-time": fmtDef(getDateTime(), compareIsoDateTime),
+  "iso-date-time": fmtDef(getDateTime(true), compareIsoDateTime),
   // duration: https://tools.ietf.org/html/rfc3339#appendix-A
   duration: /^P(?!$)((\d+Y)?(\d+M)?(\d+D)?(T(?=\d)(\d+H)?(\d+M)?(\d+S)?)?|(\d+W)?)$/,
   uri,
@@ -102,7 +102,7 @@ export const fastFormats: DefinedFormats = {
     compareTime
   ),
   "date-time": fmtDef(
-    /^\d\d\d\d-[0-1]\d-[0-3]\dt(?:[0-2]\d:[0-5]\d:[0-5]\d|23:59:60)(?:\.\d+)?(?:z|[+-]\d\d(?::?\d\d)?)$/i,
+    /^\d\d\d\d-((0[1-9])|(1[0-2]))-((0[1-9])|([1-2]\d)|(3[01]))[tT](?:(([0-1]\d)|(2[0-3])):[0-5]\d:[0-5]\d|23:59:60)(?:\.\d+)?(?:[zZ]|[+-](([0-1]\d)|(2[0-3])):[0-5]\d)$/,
     compareDateTime
   ),
   "iso-time": fmtDef(
@@ -110,7 +110,7 @@ export const fastFormats: DefinedFormats = {
     compareIsoTime
   ),
   "iso-date-time": fmtDef(
-    /^\d\d\d\d-[0-1]\d-[0-3]\d[t\s](?:[0-2]\d:[0-5]\d:[0-5]\d|23:59:60)(?:\.\d+)?(?:z|[+-]\d\d(?::?\d\d)?)?$/i,
+    /^\d\d\d\d-((0[1-9])|(1[0-2]))-((0[1-9])|([1-2]\d)|(3[01]))[t\s](?:[0-2]\d:[0-5]\d:[0-5]\d|23:59:60)(?:\.\d+)?(?:z|[+-]\d\d(?::?\d\d)?)?$/i,
     compareIsoDateTime
   ),
   // uri: https://github.com/mafintosh/is-my-json-valid/blob/master/formats.js
@@ -197,13 +197,14 @@ function compareIsoTime(t1: string, t2: string): number | undefined {
   return 0
 }
 
-const DATE_TIME_SEPARATOR = /t|\s/i
-function getDateTime(strictTimeZone?: boolean): (str: string) => boolean {
-  const time = getTime(strictTimeZone)
+const DATE_TIME_SEPARATOR = /t/i
+const ISO_DATE_TIME_SEPARATOR = /t|\s/i
+function getDateTime(iso?: boolean): (str: string) => boolean {
+  const time = getTime(!iso)
 
   return function date_time(str: string): boolean {
     // http://tools.ietf.org/html/rfc3339#section-5.6
-    const dateTime: string[] = str.split(DATE_TIME_SEPARATOR)
+    const dateTime: string[] = str.split(iso ? ISO_DATE_TIME_SEPARATOR : DATE_TIME_SEPARATOR)
     return dateTime.length === 2 && date(dateTime[0]) && time(dateTime[1])
   }
 }
@@ -218,8 +219,8 @@ function compareDateTime(dt1: string, dt2: string): number | undefined {
 
 function compareIsoDateTime(dt1: string, dt2: string): number | undefined {
   if (!(dt1 && dt2)) return undefined
-  const [d1, t1] = dt1.split(DATE_TIME_SEPARATOR)
-  const [d2, t2] = dt2.split(DATE_TIME_SEPARATOR)
+  const [d1, t1] = dt1.split(ISO_DATE_TIME_SEPARATOR)
+  const [d2, t2] = dt2.split(ISO_DATE_TIME_SEPARATOR)
   const res = compareDate(d1, d2)
   if (res === undefined) return undefined
   return res || compareTime(t1, t2)
diff --git a/tests/extras/format.json b/tests/extras/format.json
index 1a72ec4..c54d360 100644
--- a/tests/extras/format.json
+++ b/tests/extras/format.json
@@ -560,7 +560,7 @@
     ]
   },
   {
-    "description": "validation of date-time strings",
+    "description": "validation of iso-date-time strings",
     "schema": {"format": "iso-date-time"},
     "tests": [
       {
@@ -597,6 +597,132 @@
         "description": "a valid iso-date-time string (leap second)",
         "data": "2016-12-31T23:59:60Z",
         "valid": true
+      },
+      {
+        "description": "a valid iso-date-time string (space separator)",
+        "data": "2016-12-31 23:59:60Z",
+        "valid": true
+      }
+    ]
+  },
+  {
+    "description": "validation of date-time strings",
+    "schema": {"format": "date-time"},
+    "tests": [
+      {
+        "description": "a valid date-time string",
+        "data": "2016-12-31T23:59:60Z",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2015-12-31t23:59:60Z",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2015-02-11t22:59:22Z",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2020-01-01T20:00:00.000Z",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2020-01-01T20:00:00.000-00:00",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2023-05-04T01:14:00+21:00",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2023-05-04T01:14:10+16:20",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2023-05-04T01:14:21+09:50",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2023-05-04T01:14:21-04:31",
+        "valid": true
+      },
+      {
+        "description": "a valid date-time string",
+        "data": "2023-05-04T01:14:21-23:59",
+        "valid": true
+      },
+      {
+        "description": "an invalid date-time string (invalid month)",
+        "data": "2016-15-31T23:59:60Z",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid month)",
+        "data": "2015-00-11t22:59:22+00:00",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid day)",
+        "data": "2015-01-00T22:59:22+00:00",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator)",
+        "data": "2016-12-31 23:59:60Z",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid time)",
+        "data": "2015-02-11t24:59:22Z",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator and time-offset)",
+        "data": "2020-01-01 20:00:00.000",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator)",
+        "data": "2020-01-01 20:00:00.000Z",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator)",
+        "data": "2023-05-04\t01:14:00+21:00",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator)",
+        "data": "2023-05-04\r01:14:10+16:20",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid timezone)",
+        "data": "2015-02-11t22:59:22+24:30",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator)",
+        "data": "2023-05-04\n01:14:21+09:50",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid separator)",
+        "data": "2023-05-04\n01:14:21-04:31",
+        "valid": false
+      },
+      {
+        "description": "an invalid date-time string (invalid time-offset)",
+        "data": "2023-05-04t01:14:21-04:31:00",
+        "valid": false
       }
     ]
   },
diff --git a/tests/index.spec.ts b/tests/index.spec.ts
index b434921..352531a 100644
--- a/tests/index.spec.ts
+++ b/tests/index.spec.ts
@@ -25,7 +25,7 @@ describe("addFormats options", () => {
   })
 
   test("should support validation mode", () => {
-    addFormats(ajv, {mode: "fast", formats: ["date", "time"]})
+    addFormats(ajv, {mode: "fast", formats: ["date", "time", "date-time", "iso-date-time"]})
     const validateDate = ajv.compile({format: "date"})
     expect(validateDate("2020-09-17")).toEqual(true)
     expect(validateDate("2020-09-35")).toEqual(true)
@@ -35,6 +35,35 @@ describe("addFormats options", () => {
     expect(validateTime("17:27:38Z")).toEqual(true)
     expect(validateTime("25:27:38Z")).toEqual(true)
     expect(validateTime("17:27")).toEqual(false)
+
+    const validateDatetime = ajv.compile({format: "date-time"})
+    expect(validateDatetime("2016-12-31T23:59:60Z")).toEqual(true)
+    expect(validateDatetime("2015-12-31t23:59:60Z")).toEqual(true)
+    expect(validateDatetime("2015-02-11t22:59:22Z")).toEqual(true)
+    expect(validateDatetime("2020-01-01T20:00:00.000Z")).toEqual(true)
+    expect(validateDatetime("2020-01-01T20:00:00.000Z")).toEqual(true)
+    expect(validateDatetime("2023-05-04T01:14:00+21:00")).toEqual(true)
+    expect(validateDatetime("2023-05-04T01:14:10+16:20")).toEqual(true)
+    expect(validateDatetime("2023-05-04T01:14:21+09:50")).toEqual(true)
+    expect(validateDatetime("2023-05-04T01:14:21-04:31")).toEqual(true)
+    expect(validateDatetime("2023-05-04T01:14:21-23:59")).toEqual(true)
+    expect(validateDatetime("2016-15-31T23:59:60Z")).toEqual(false)
+    expect(validateDatetime("2015-00-11t22:59:22+00:00")).toEqual(false)
+    expect(validateDatetime("2015-01-00T22:59:22+00:00")).toEqual(false)
+    expect(validateDatetime("2016-12-31 23:59:60Z")).toEqual(false)
+    expect(validateDatetime("2015-02-11t24:59:22Z")).toEqual(false)
+    expect(validateDatetime("2020-01-01 20:00:00.000")).toEqual(false)
+    expect(validateDatetime("2020-01-01 20:00:00.000Z")).toEqual(false)
+    expect(validateDatetime("2023-05-04\t01:14:00+21:00")).toEqual(false)
+    expect(validateDatetime("2023-05-04\r01:14:10+16:20")).toEqual(false)
+    expect(validateDatetime("2015-02-11t22:59:22+24:30")).toEqual(false)
+    expect(validateDatetime("2023-05-04\n01:14:21+09:50")).toEqual(false)
+    expect(validateDatetime("2023-05-04\n01:14:21-04:31")).toEqual(false)
+    expect(validateDatetime("2023-05-04t01:14:21-04:31:00")).toEqual(false)
+
+    const validateIsoDatetime = ajv.compile({format: "iso-date-time"})
+    expect(validateIsoDatetime("2016-12-31 23:59:60Z")).toEqual(true)
+    expect(validateIsoDatetime("2016-13-31 23:59:60Z")).toEqual(false)
   })
 })