diff --git a/CHANGES.rst b/CHANGES.rst
index 6b7a418315..aefc135b35 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -28,6 +28,7 @@ mast
 - Filtering by file extension or by a string column is now case-insensitive in ``MastMissions.filter_products``
   and ``Observations.filter_products``. [#3427]
 
+- Raise informative error if ``MastMissions`` query radius is too large. [#3447]
 
 Infrastructure, Utility and Other Changes and Additions
 -------------------------------------------------------
diff --git a/astroquery/mast/missions.py b/astroquery/mast/missions.py
index ba87307d30..38af7370a7 100644
--- a/astroquery/mast/missions.py
+++ b/astroquery/mast/missions.py
@@ -47,6 +47,9 @@ class MastMissionsClass(MastQueryWithLogin):
                              'spectral_type', 'bmv0_mag', 'u_mag', 'b_mag', 'v_mag', 'gaia_g_mean_mag', 'star_mass',
                              'instrument', 'grating', 'filter', 'observation_id']
 
+    # maximum supported query radius
+    _max_query_radius = 30 * u.arcmin
+
     def __init__(self, *, mission='hst', mast_token=None):
         super().__init__(mast_token=mast_token)
 
@@ -217,6 +220,7 @@ def query_region_async(self, coordinates, *, radius=3*u.arcmin, limit=5000, offs
             Default is 3 arcminutes. The radius around the coordinates to search within.
             The string must be parsable by `~astropy.coordinates.Angle`. The
             appropriate `~astropy.units.Quantity` object from `~astropy.units` may also be used.
+            The maximum supported query radius is 30 arcminutes.
         limit : int
             Default is 5000. The maximum number of dataset IDs in the results.
         offset : int
@@ -235,6 +239,11 @@ def query_region_async(self, coordinates, *, radius=3*u.arcmin, limit=5000, offs
         Returns
         -------
         response : list of `~requests.Response`
+
+        Raises
+        ------
+        InvalidQueryError
+            If the query radius is larger than the limit (30 arcminutes).
         """
 
         self.limit = limit
@@ -249,6 +258,11 @@ def query_region_async(self, coordinates, *, radius=3*u.arcmin, limit=5000, offs
         # If radius is just a number, assume arcminutes
         radius = coord.Angle(radius, u.arcmin)
 
+        if radius > self._max_query_radius:
+            raise InvalidQueryError(
+                f"Query radius too large. Must be ≤{self._max_query_radius}, got {radius}."
+            )
+
         # Dataset ID column should always be returned
         if select_cols:
             select_cols.append(self.dataset_kwds.get(self.mission, None))
@@ -284,6 +298,7 @@ def query_criteria_async(self, *, coordinates=None, objectname=None, radius=3*u.
             Default is 3 arcminutes. The radius around the coordinates to search within.
             The string must be parsable by `~astropy.coordinates.Angle`. The
             appropriate `~astropy.units.Quantity` object from `~astropy.units` may also be used.
+            The maximum supported query radius is 30 arcminutes.
         limit : int
             Default is 5000. The maximum number of dataset IDs in the results.
         offset : int
@@ -310,6 +325,11 @@ def query_criteria_async(self, *, coordinates=None, objectname=None, radius=3*u.
         Returns
         -------
         response : list of `~requests.Response`
+
+        Raises
+        ------
+        InvalidQueryError
+            If the query radius is larger than the limit (30 arcminutes).
         """
 
         self.limit = limit
@@ -327,6 +347,11 @@ def query_criteria_async(self, *, coordinates=None, objectname=None, radius=3*u.
         # if radius is just a number we assume degrees
         radius = coord.Angle(radius, u.arcmin)
 
+        if radius > self._max_query_radius:
+            raise InvalidQueryError(
+                f"Query radius too large. Must be ≤{self._max_query_radius}, got {radius}."
+            )
+
         # Dataset ID column should always be returned
         if select_cols:
             select_cols.append(self.dataset_kwds.get(self.mission, None))
diff --git a/astroquery/mast/tests/test_mast.py b/astroquery/mast/tests/test_mast.py
index 9d90da325e..63867224d3 100644
--- a/astroquery/mast/tests/test_mast.py
+++ b/astroquery/mast/tests/test_mast.py
@@ -510,6 +510,22 @@ def test_missions_get_dataset_kwd(patch_post, caplog):
     with caplog.at_level('WARNING', logger='astroquery'):
         assert 'The mission "unknown" does not have a known dataset ID keyword' in caplog.text
 
+
+@pytest.mark.parametrize(
+    'method, kwargs,',
+    [['query_region', dict()],
+     ['query_criteria', dict(ang_sep=0.6)]]
+)
+def test_missions_radius_too_large(method, kwargs, patch_post):
+    m = mast.MastMissions(mission='jwst')
+    coordinates = SkyCoord(0, 0, unit=u.deg)
+    radius = m._max_query_radius + 0.1 * u.deg
+    with pytest.raises(
+        InvalidQueryError, match='Query radius too large. Must be*'
+    ):
+        getattr(m, method)(coordinates=coordinates, radius=radius, **kwargs)
+
+
 ###################
 # MastClass tests #
 ###################