diff --git a/packages/import/src/json-resume.test.ts b/packages/import/src/json-resume.test.ts
index 3e8a12019..434abf91f 100644
--- a/packages/import/src/json-resume.test.ts
+++ b/packages/import/src/json-resume.test.ts
@@ -13,6 +13,29 @@ describe("parseJSONResume", () => {
 		expect(() => parseJSONResume(invalid)).toThrow();
 	});
 
+	it.each([
+		"2024-00",
+		"2024-13",
+		"2024-19",
+		"2024-00-01",
+		"2024-13-01",
+		"2024-01-00",
+		"2024-01-32",
+		"2024-1",
+		"2024-1-5",
+	])("rejects the malformed date %s and names the field", (startDate) => {
+		const json = JSON.stringify({ work: [{ name: "Acme", position: "Engineer", startDate }] });
+		expect(() => parseJSONResume(json)).toThrow(/work\.0\.startDate \(Must be a valid ISO 8601 date/);
+	});
+
+	it.each(["2024", "2024-01", "2024-12", "2024-02-29", "1999-12-31"])(
+		"still accepts the valid date %s",
+		(startDate) => {
+			const json = JSON.stringify({ work: [{ name: "Acme", position: "Engineer", startDate }] });
+			expect(() => parseJSONResume(json)).not.toThrow();
+		},
+	);
+
 	it("imports an empty JSON Resume into a baseline ResumeData", () => {
 		const result = parseJSONResume("{}");
 		// Defaults preserve a name field even when unset by input.
diff --git a/packages/import/src/json-resume.tsx b/packages/import/src/json-resume.tsx
index 591282911..d344f4106 100644
--- a/packages/import/src/json-resume.tsx
+++ b/packages/import/src/json-resume.tsx
@@ -23,7 +23,7 @@ const createItemWebsite = (url?: string, label?: string) => ({
 const iso8601 = z
 	.string()
 	.regex(
-		/^([1-2][0-9]{3}-[0-1][0-9]-[0-3][0-9]|[1-2][0-9]{3}-[0-1][0-9]|[1-2][0-9]{3})$/,
+		/^([1-2][0-9]{3}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12][0-9]|3[01])|[1-2][0-9]{3}-(?:0[1-9]|1[0-2])|[1-2][0-9]{3})$/,
 		"Must be a valid ISO 8601 date (YYYY, YYYY-MM, or YYYY-MM-DD)",
 	);