diff --git a/src/main/java/graphql/scalars/datetime/DateTimeScalar.java b/src/main/java/graphql/scalars/datetime/DateTimeScalar.java
index c920c13..41c8000 100644
--- a/src/main/java/graphql/scalars/datetime/DateTimeScalar.java
+++ b/src/main/java/graphql/scalars/datetime/DateTimeScalar.java
@@ -14,6 +14,8 @@
 import java.time.DateTimeException;
 import java.time.OffsetDateTime;
 import java.time.ZonedDateTime;
+import java.time.Instant;
+import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.time.format.DateTimeFormatterBuilder;
 import java.time.format.DateTimeParseException;
@@ -50,6 +52,8 @@ public String serialize(Object input, GraphQLContext graphQLContext, Locale loca
                     offsetDateTime = (OffsetDateTime) input;
                 } else if (input instanceof ZonedDateTime) {
                     offsetDateTime = ((ZonedDateTime) input).toOffsetDateTime();
+                } else if (input instanceof Instant){
+                    offsetDateTime = ((Instant) input).atOffset(ZoneOffset.UTC);
                 } else if (input instanceof String) {
                     offsetDateTime = parseOffsetDateTime(input.toString(), CoercingSerializeException::new);
                 } else {
@@ -73,6 +77,8 @@ public OffsetDateTime parseValue(Object input, GraphQLContext graphQLContext, Lo
                     offsetDateTime = (OffsetDateTime) input;
                 } else if (input instanceof ZonedDateTime) {
                     offsetDateTime = ((ZonedDateTime) input).toOffsetDateTime();
+                } else if (input instanceof Instant){
+                    offsetDateTime = ((Instant)input).atOffset(ZoneOffset.UTC);
                 } else if (input instanceof String) {
                     offsetDateTime = parseOffsetDateTime(input.toString(), CoercingParseValueException::new);
                 } else {
diff --git a/src/test/groovy/graphql/scalars/datetime/DateTimeScalarTest.groovy b/src/test/groovy/graphql/scalars/datetime/DateTimeScalarTest.groovy
index d8cb915..6b7379b 100644
--- a/src/test/groovy/graphql/scalars/datetime/DateTimeScalarTest.groovy
+++ b/src/test/groovy/graphql/scalars/datetime/DateTimeScalarTest.groovy
@@ -8,6 +8,7 @@ import graphql.schema.CoercingParseValueException
 import graphql.schema.CoercingSerializeException
 import spock.lang.Unroll
 
+import static graphql.scalars.util.TestKit.mkInstant
 import static graphql.scalars.util.TestKit.mkIntValue
 import static graphql.scalars.util.TestKit.mkLocalDT
 import static graphql.scalars.util.TestKit.mkOffsetDT
@@ -33,6 +34,7 @@ class DateTimeScalarTest extends AbstractScalarTest {
         "2022-11-24T01:00:01.02+00:00"  | mkOffsetDT("2022-11-24T01:00:01.02+00:00")
         mkOffsetDT(year: 1980, hour: 3) | mkOffsetDT("1980-08-08T03:10:09+10:00")
         mkZonedDT(year: 1980, hour: 3)  | mkOffsetDT("1980-08-08T03:10:09+10:00")
+        mkInstant(year: 1980, hour: 3)  | mkOffsetDT("1980-08-08T03:10:09.00Z")
     }
 
     @Unroll
@@ -51,6 +53,7 @@ class DateTimeScalarTest extends AbstractScalarTest {
         "2022-11-24T01:00:01.02+00:00"  | mkStringValue("2022-11-24T01:00:01.020Z")
         mkOffsetDT(year: 1980, hour: 3) | mkStringValue("1980-08-08T03:10:09.000+10:00")
         mkZonedDT(year: 1980, hour: 3)  | mkStringValue("1980-08-08T03:10:09.000+10:00")
+        mkInstant(year: 1980, hour: 3)  | mkStringValue("1980-08-08T03:10:09.000Z")
     }
 
     @Unroll
@@ -97,6 +100,7 @@ class DateTimeScalarTest extends AbstractScalarTest {
         "2022-11-24T01:00:01.02+00:00"  | "2022-11-24T01:00:01.020Z"
         mkOffsetDT(year: 1980, hour: 3) | "1980-08-08T03:10:09.000+10:00"
         mkZonedDT(year: 1980, hour: 3)  | "1980-08-08T03:10:09.000+10:00"
+        mkInstant(year: 1980, hour: 3)  | "1980-08-08T03:10:09.000Z"
     }
 
     def "datetime serialisation bad inputs"() {
diff --git a/src/test/groovy/graphql/scalars/util/TestKit.groovy b/src/test/groovy/graphql/scalars/util/TestKit.groovy
index 27aafdd..4eca04a 100644
--- a/src/test/groovy/graphql/scalars/util/TestKit.groovy
+++ b/src/test/groovy/graphql/scalars/util/TestKit.groovy
@@ -7,6 +7,7 @@ import graphql.scalars.country.code.CountryCode
 
 import java.awt.*
 import java.time.Duration
+import java.time.Instant
 import java.time.LocalDate
 import java.time.LocalDateTime
 import java.time.LocalTime
@@ -54,6 +55,11 @@ class TestKit {
                 args.min ?: 10, args.secs ?: 9, args.nanos ?: 0, ZoneId.ofOffset("", ZoneOffset.ofHours(10)))
     }
 
+    static Instant mkInstant(args) {
+        OffsetDateTime.of(args.year ?: 1969, args.month ?: 8, args.day ?: 8, args.hour ?: 11,
+                args.min ?: 10, args.secs ?: 9, args.nanos ?: 0, ZoneOffset.UTC).toInstant()
+    }
+
     static Duration mkDuration(String s) {
         Duration.parse(s)
     }