diff --git a/datetime/src/main/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializer.java b/datetime/src/main/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializer.java
index 4a599941..c046aaf1 100644
--- a/datetime/src/main/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializer.java
+++ b/datetime/src/main/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializer.java
@@ -2,7 +2,6 @@
 
 import java.time.DateTimeException;
 import java.time.ZonedDateTime;
-import java.time.format.DateTimeFormatter;
 
 import tools.jackson.core.JacksonException;
 import tools.jackson.databind.DeserializationContext;
@@ -11,7 +10,7 @@ public class ZonedDateTimeKeyDeserializer extends Jsr310KeyDeserializer {
 
     public static final ZonedDateTimeKeyDeserializer INSTANCE = new ZonedDateTimeKeyDeserializer();
 
-    private ZonedDateTimeKeyDeserializer() {
+    protected ZonedDateTimeKeyDeserializer() {
         // singleton
     }
 
@@ -19,9 +18,9 @@ private ZonedDateTimeKeyDeserializer() {
     protected ZonedDateTime deserialize(String key, DeserializationContext ctxt)
         throws JacksonException
     {
-        // not serializing timezone data yet
         try {
-            return ZonedDateTime.parse(key, DateTimeFormatter.ISO_OFFSET_DATE_TIME);
+            // Not supplying a formatter allows the use of all supported formats
+            return ZonedDateTime.parse(key);
         } catch (DateTimeException e) {
             return _handleDateTimeException(ctxt, ZonedDateTime.class, e, key);
         }
diff --git a/datetime/src/test/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializerTest.java b/datetime/src/test/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializerTest.java
new file mode 100644
index 00000000..416ffd54
--- /dev/null
+++ b/datetime/src/test/java/tools/jackson/datatype/jsr310/deser/key/ZonedDateTimeKeyDeserializerTest.java
@@ -0,0 +1,72 @@
+package tools.jackson.datatype.jsr310.deser.key;
+
+import org.junit.Test;
+
+import tools.jackson.core.type.TypeReference;
+
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.datatype.jsr310.ModuleTestBase;
+
+import java.time.ZonedDateTime;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assume.*;
+
+// for [modules-java8#306]
+public class ZonedDateTimeKeyDeserializerTest
+    extends ModuleTestBase
+{
+    private final ObjectMapper MAPPER = newMapper();
+    private final TypeReference<Map<ZonedDateTime, String>> MAP_TYPE_REF
+        = new TypeReference<Map<ZonedDateTime, String>>() {};
+
+    @Test
+    public void Instant_style_can_be_deserialized() throws Exception {
+        Map<ZonedDateTime, String> map = MAPPER.readValue(getMap("2015-07-24T12:23:34.184Z"),
+                MAP_TYPE_REF);
+        Map.Entry<ZonedDateTime, String> entry = map.entrySet().iterator().next();
+        assertEquals("2015-07-24T12:23:34.184Z", entry.getKey().toString());
+    }
+
+    @Test
+    public void ZonedDateTime_with_zone_name_can_be_deserialized() throws Exception {
+        Map<ZonedDateTime, String> map = MAPPER.readValue(getMap("2015-07-24T12:23:34.184Z[UTC]"),
+                MAP_TYPE_REF);
+        Map.Entry<ZonedDateTime, String> entry = map.entrySet().iterator().next();
+        assertEquals("2015-07-24T12:23:34.184Z[UTC]", entry.getKey().toString());
+    }
+
+    @Test
+    public void ZonedDateTime_with_place_name_can_be_deserialized() throws Exception {
+        assumeFalse(System.getProperty("java.version").startsWith("1.8"));
+
+        Map<ZonedDateTime, String> map = MAPPER.readValue(getMap("2015-07-24T12:23:34.184Z[Europe/London]"),
+                MAP_TYPE_REF);
+        Map.Entry<ZonedDateTime, String> entry = map.entrySet().iterator().next();
+        assertEquals("2015-07-24T13:23:34.184+01:00[Europe/London]", entry.getKey().toString());
+    }
+
+    @Test
+    public void ZonedDateTime_with_place_name_can_be_deserialized_Java_8() throws Exception {
+        // Java 8 parses this format incorrectly due to https://bugs.openjdk.org/browse/JDK-8066982
+        assumeTrue(System.getProperty("java.version").startsWith("1.8"));
+
+        Map<ZonedDateTime, String> map = MAPPER.readValue(getMap("2015-07-24T12:23:34.184Z[Europe/London]"),
+                MAP_TYPE_REF);
+        Map.Entry<ZonedDateTime, String> entry = map.entrySet().iterator().next();
+        assertEquals("2015-07-24T12:23:34.184+01:00[Europe/London]", entry.getKey().toString());
+    }
+
+    @Test
+    public void ZonedDateTime_with_offset_can_be_deserialized() throws Exception {
+        Map<ZonedDateTime, String> map = MAPPER.readValue(getMap("2015-07-24T12:23:34.184+02:00"),
+                MAP_TYPE_REF);
+        Map.Entry<ZonedDateTime, String> entry = map.entrySet().iterator().next();
+        assertEquals("2015-07-24T12:23:34.184+02:00", entry.getKey().toString());
+    }
+
+    private static String getMap(String input) {
+        return "{\"" + input + "\": \"This is a string\"}";
+    }
+}
diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
index 5ee2de10..bfad40fc 100644
--- a/release-notes/VERSION-2.x
+++ b/release-notes/VERSION-2.x
@@ -8,6 +8,15 @@ Modules:
 === Releases ===
 ------------------------------------------------------------------------
 
+2.18.0 (not yet released)
+
+No changes since 2.17
+
+2.17.1 (not yet released)
+
+#306: Only `DateTimeFormatter.ISO_OFFSET_DATE_TIME` accepted by `ZonedDateTimeKeyDeserializer`
+ (fix contributed by @caluml)
+
 2.17.0 (12-Mar-2024)
 
 #274: Deserializing `java.time.Month` from an int causes an off-by-one