diff --git a/changelog.d/9872-mock-timers-validation.md b/changelog.d/9872-mock-timers-validation.md
new file mode 100644
index 0000000000..d068f1dac0
--- /dev/null
+++ b/changelog.d/9872-mock-timers-validation.md
@@ -0,0 +1,4 @@
+### Fixed
+
+- Match Node 26 mock-timer validation by accepting default primitive options
+  and non-negative infinite clock advances.
diff --git a/crates/perry-runtime/src/node_submodules/test.rs b/crates/perry-runtime/src/node_submodules/test.rs
index 8b3b032340..cb70c0b994 100644
--- a/crates/perry-runtime/src/node_submodules/test.rs
+++ b/crates/perry-runtime/src/node_submodules/test.rs
@@ -228,7 +228,7 @@ extern "C" fn mock_timers_tick(_closure: *const ClosureHeader, ms: f64) -> f64 {
     let delay = if is_undefined_value(ms) {
         1.0
     } else {
-        validate_mock_timer_number("time", ms)
+        validate_mock_timer_number("time", ms, false)
     };
     crate::timer::js_mock_timers_tick(delay);
     undefined_value()
@@ -240,7 +240,7 @@ extern "C" fn mock_timers_run_all(_closure: *const ClosureHeader) -> f64 {
 }
 
 extern "C" fn mock_timers_set_time(_closure: *const ClosureHeader, ms: f64) -> f64 {
-    let time = validate_mock_timer_number("time", ms);
+    let time = validate_mock_timer_number("time", ms, false);
     crate::timer::js_mock_timers_set_time(time);
     undefined_value()
 }
@@ -250,15 +250,15 @@ extern "C" fn mock_timers_reset(_closure: *const ClosureHeader) -> f64 {
     undefined_value()
 }
 
-fn validate_mock_timer_number(arg: &str, value: f64) -> f64 {
+fn validate_mock_timer_number(arg: &str, value: f64, reject_nan: bool) -> f64 {
     let js = JSValue::from_bits(value.to_bits());
     if !crate::fs::validate::is_numeric(js) {
         throw_invalid_arg_type(arg, "number", value);
     }
     let n = crate::builtins::js_number_coerce(value);
-    if !n.is_finite() || n < 0.0 {
+    if n < 0.0 || (reject_nan && n.is_nan()) {
         let message = format!(
-            "The \"{}\" argument must be a non-negative finite number. Received {}",
+            "The \"{}\" argument must be a non-negative number. Received {}",
             arg,
             crate::fs::validate::describe_received(value)
         );
@@ -271,16 +271,13 @@ fn parse_mock_timer_options(options: f64) -> (u32, f64) {
     let mut apis_value = options;
     let mut now = 0.0;
     let js = JSValue::from_bits(options.to_bits());
-    if js.is_undefined() {
+    if js.is_undefined() || js.is_null() || !js.is_pointer() {
         return (crate::timer::MOCK_TIMERS_ALL_APIS, now);
     }
     if !is_array_value(options) {
-        if js.is_null() || !js.is_pointer() {
-            throw_invalid_arg_type("options", "object", options);
-        }
         apis_value = object_property(options, b"apis").unwrap_or(undefined_value());
         if let Some(now_value) = object_property(options, b"now") {
-            now = validate_mock_timer_number("options.now", now_value);
+            now = validate_mock_timer_number("options.now", now_value, true);
         }
     }
     if JSValue::from_bits(apis_value.to_bits()).is_undefined() {
diff --git a/crates/perry-runtime/src/node_submodules/test_unit_tests.rs b/crates/perry-runtime/src/node_submodules/test_unit_tests.rs
index a54218a18c..c27a4bc471 100644
--- a/crates/perry-runtime/src/node_submodules/test_unit_tests.rs
+++ b/crates/perry-runtime/src/node_submodules/test_unit_tests.rs
@@ -175,3 +175,21 @@ fn mock_timers_exposes_dispose_as_reset() {
     assert!(is_callable_value(symbol_method));
     assert_ne!(symbol_method.to_bits(), reset.to_bits());
 }
+
+#[test]
+fn mock_timers_accepts_null_and_primitives_as_default_options() {
+    for options in [f64::from_bits(crate::value::TAG_NULL), 1.0] {
+        let (apis, now) = parse_mock_timer_options(options);
+
+        assert_eq!(apis, crate::timer::MOCK_TIMERS_ALL_APIS);
+        assert_eq!(now, 0.0);
+    }
+}
+
+#[test]
+fn mock_timer_clock_values_accept_positive_infinity() {
+    assert_eq!(
+        validate_mock_timer_number("time", f64::INFINITY, false),
+        f64::INFINITY
+    );
+}
diff --git a/test-parity/node-suite/test/mock-timers/validation.ts b/test-parity/node-suite/test/mock-timers/validation.ts
index 6f69fbc0fb..d33f949fc9 100644
--- a/test-parity/node-suite/test/mock-timers/validation.ts
+++ b/test-parity/node-suite/test/mock-timers/validation.ts
@@ -12,7 +12,10 @@ function codeOf(fn: () => void): string {
 console.log("runAll disabled:", codeOf(() => mock.timers.runAll()));
 console.log("tick disabled:", codeOf(() => mock.timers.tick()));
 console.log("setTime disabled:", codeOf(() => mock.timers.setTime(1)));
-console.log("bad options:", codeOf(() => mock.timers.enable(null as any)));
+console.log("null options:", codeOf(() => mock.timers.enable(null as any)));
+mock.timers.reset();
+console.log("number options:", codeOf(() => mock.timers.enable(1 as any)));
+mock.timers.reset();
 console.log("bad api type:", codeOf(() => mock.timers.enable({ apis: [1 as any] })));
 console.log("bad now:", codeOf(() => mock.timers.enable({ now: -1 })));
 mock.timers.enable({ apis: ["Date"], now: 0 });