diff --git a/src/types/index.d.ts b/src/types/index.d.ts
index 32831adc88c..8a6915fd393 100644
--- a/src/types/index.d.ts
+++ b/src/types/index.d.ts
@@ -3430,7 +3430,7 @@ export type TimeScaleTimeOptions = {
   /**
    * Custom parser for dates.
    */
-  parser: string | ((v: unknown) => number);
+  parser?: string | ((v: unknown) => number);
   /**
    * If defined, dates will be rounded to the start of this unit. See Time Units below for the allowed units.
    */
@@ -3450,7 +3450,7 @@ export type TimeScaleTimeOptions = {
   /**
    * The format string to use for the tooltip.
    */
-  tooltipFormat: string;
+  tooltipFormat?: string;
   /**
    * If defined, will force the unit to be a certain type. See Time Units section below for details.
    * @default false
diff --git a/test/types/scales/time_options.ts b/test/types/scales/time_options.ts
new file mode 100644
index 00000000000..a088af76dd0
--- /dev/null
+++ b/test/types/scales/time_options.ts
@@ -0,0 +1,24 @@
+import type { TimeScaleTimeOptions } from '../../../src/types.js';
+
+// `time.parser` and `time.tooltipFormat` have no default value, so they must stay
+// optional when the resolved time scale options are referenced directly.
+const minimal: TimeScaleTimeOptions = {
+  unit: 'year',
+  round: false,
+  isoWeekday: false,
+  minUnit: 'millisecond',
+  displayFormats: {
+    month: 'yy'
+  }
+};
+
+const withParser: TimeScaleTimeOptions = {
+  ...minimal,
+  parser: 'yyyy-MM-dd',
+  tooltipFormat: 'eeee, MMM dd, yyyy'
+};
+
+const withParserFunction: TimeScaleTimeOptions = {
+  ...minimal,
+  parser: (value: unknown) => Number(value)
+};