diff --git a/pyproject.toml b/pyproject.toml
index 7e240390..30f8df85 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -101,6 +101,8 @@ ignore = [
     "E501",
     # consider `[meta, header, *data]` instead of concatenation
     "RUF005",
+    # Use `X | Y` in `isinstance` call instead of `(X, Y)`
+    "UP038",
     # multi-line-summary-first-line
     "D212",
     # one-blank-line-before-class
diff --git a/src/virtualship/expedition/ship_config.py b/src/virtualship/expedition/ship_config.py
index 7bb41e84..5609c182 100644
--- a/src/virtualship/expedition/ship_config.py
+++ b/src/virtualship/expedition/ship_config.py
@@ -8,6 +8,8 @@
 import pydantic
 import yaml
 
+from virtualship.utils import _validate_numeric_mins_to_timedelta
+
 
 class ArgoFloatConfig(pydantic.BaseModel):
     """Configuration for argos floats."""
@@ -37,6 +39,10 @@ class ADCPConfig(pydantic.BaseModel):
     def _serialize_period(self, value: timedelta, _info):
         return value.total_seconds() / 60.0
 
+    @pydantic.field_validator("period", mode="before")
+    def _validate_period(cls, value: int | float | timedelta) -> timedelta:
+        return _validate_numeric_mins_to_timedelta(value)
+
 
 class CTDConfig(pydantic.BaseModel):
     """Configuration for CTD instrument."""
@@ -55,6 +61,10 @@ class CTDConfig(pydantic.BaseModel):
     def _serialize_stationkeeping_time(self, value: timedelta, _info):
         return value.total_seconds() / 60.0
 
+    @pydantic.field_validator("stationkeeping_time", mode="before")
+    def _validate_stationkeeping_time(cls, value: int | float | timedelta) -> timedelta:
+        return _validate_numeric_mins_to_timedelta(value)
+
 
 class ShipUnderwaterSTConfig(pydantic.BaseModel):
     """Configuration for underwater ST."""
@@ -71,6 +81,10 @@ class ShipUnderwaterSTConfig(pydantic.BaseModel):
     def _serialize_period(self, value: timedelta, _info):
         return value.total_seconds() / 60.0
 
+    @pydantic.field_validator("period", mode="before")
+    def _validate_period(cls, value: int | float | timedelta) -> timedelta:
+        return _validate_numeric_mins_to_timedelta(value)
+
 
 class DrifterConfig(pydantic.BaseModel):
     """Configuration for drifters."""
@@ -88,6 +102,10 @@ class DrifterConfig(pydantic.BaseModel):
     def _serialize_lifetime(self, value: timedelta, _info):
         return value.total_seconds() / 60.0
 
+    @pydantic.field_validator("lifetime", mode="before")
+    def _validate_lifetime(cls, value: int | float | timedelta) -> timedelta:
+        return _validate_numeric_mins_to_timedelta(value)
+
 
 class XBTConfig(pydantic.BaseModel):
     """Configuration for xbt instrument."""
diff --git a/src/virtualship/utils.py b/src/virtualship/utils.py
index 43608b60..ec97321e 100644
--- a/src/virtualship/utils.py
+++ b/src/virtualship/utils.py
@@ -1,3 +1,4 @@
+from datetime import timedelta
 from functools import lru_cache
 from importlib.resources import files
 from typing import TextIO
@@ -151,3 +152,10 @@ def mfp_to_yaml(excel_file_path: str, yaml_output_path: str):  # noqa: D417
 
     # Save to YAML file
     schedule.to_yaml(yaml_output_path)
+
+
+def _validate_numeric_mins_to_timedelta(value: int | float | timedelta) -> timedelta:
+    """Convert minutes to timedelta when reading."""
+    if isinstance(value, timedelta):
+        return value
+    return timedelta(minutes=value)
diff --git a/tests/expedition/test_simulate_schedule.py b/tests/expedition/test_simulate_schedule.py
index 01544c42..ef090b4e 100644
--- a/tests/expedition/test_simulate_schedule.py
+++ b/tests/expedition/test_simulate_schedule.py
@@ -46,3 +46,11 @@ def test_simulate_schedule_too_far() -> None:
     result = simulate_schedule(projection, ship_config, schedule)
 
     assert isinstance(result, ScheduleProblem)
+
+
+def test_time_in_minutes_in_ship_schedule() -> None:
+    """Test whether the pydantic serializer picks up the time *in minutes* in the ship schedule."""
+    ship_config = ShipConfig.from_yaml("expedition_dir/ship_config.yaml")
+    assert ship_config.adcp_config.period == timedelta(minutes=5)
+    assert ship_config.ctd_config.stationkeeping_time == timedelta(minutes=20)
+    assert ship_config.ship_underwater_st_config.period == timedelta(minutes=5)