diff --git a/src/conversions/jiff.rs b/src/conversions/jiff.rs
index 593811f7641..9d2211431cc 100644
--- a/src/conversions/jiff.rs
+++ b/src/conversions/jiff.rs
@@ -68,6 +68,9 @@ fn datetime_to_pydatetime<'py>(
     fold: bool,
     timezone: Option<&TimeZone>,
 ) -> PyResult<Bound<'py, PyDateTime>> {
+    let micros = datetime.subsec_nanosecond() / 1000;
+    // SAFETY: `subsec_nanosecond()` [0, 999_999_999], after / 1000 always non-negative
+    unsafe { core::hint::assert_unchecked(micros >= 0) };
     PyDateTime::new_with_fold(
         py,
         datetime.year().into(),
@@ -76,7 +79,7 @@ fn datetime_to_pydatetime<'py>(
         datetime.hour().try_into()?,
         datetime.minute().try_into()?,
         datetime.second().try_into()?,
-        (datetime.subsec_nanosecond() / 1000).try_into()?,
+        micros as u32,
         timezone
             .map(|tz| tz.into_pyobject(py))
             .transpose()?
@@ -87,10 +90,17 @@ fn datetime_to_pydatetime<'py>(
 
 #[cfg(not(Py_LIMITED_API))]
 fn pytime_to_time(time: &impl PyTimeAccess) -> PyResult<Time> {
+    // SAFETY: Python guarantees hour belongs to [0,23],
+    // minute / second belong to [0,59], all < 128
+    unsafe {
+        core::hint::assert_unchecked(time.get_hour() < 128);
+        core::hint::assert_unchecked(time.get_minute() < 128);
+        core::hint::assert_unchecked(time.get_second() < 128);
+    }
     Ok(Time::new(
-        time.get_hour().try_into()?,
-        time.get_minute().try_into()?,
-        time.get_second().try_into()?,
+        time.get_hour() as i8,
+        time.get_minute() as i8,
+        time.get_second() as i8,
         (time.get_microsecond() * 1000).try_into()?,
     )?)
 }
diff --git a/src/conversions/num_bigint.rs b/src/conversions/num_bigint.rs
index 2a0c101ef89..da0638d9d40 100644
--- a/src/conversions/num_bigint.rs
+++ b/src/conversions/num_bigint.rs
@@ -278,10 +278,14 @@ fn int_to_u32_vec<const SIGNED: bool>(long: &Bound<'_, PyInt>) -> PyResult<Vec<u
     let n_digits = n_bytes_unsigned.div_ceil(4);
     buffer.reserve_exact(n_digits);
     unsafe {
+        // SAFETY: `n_bytes_unsigned <= isize::MAX` (try_into above) and
+        // `n_digits * 4 <= n_bytes_unsigned + 3`
+        #[expect(clippy::checked_conversions)]
+        core::hint::assert_unchecked(n_digits * 4 <= isize::MAX as usize);
         ffi::PyLong_AsNativeBytes(
             long.as_ptr().cast(),
             buffer.as_mut_ptr().cast(),
-            (n_digits * 4).try_into().unwrap(),
+            (n_digits * 4) as isize,
             flags,
         );
         buffer.set_len(n_digits);