diff --git a/suitcase/mongo_normalized/__init__.py b/suitcase/mongo_normalized/__init__.py
index 6a2b478..f84f6d2 100644
--- a/suitcase/mongo_normalized/__init__.py
+++ b/suitcase/mongo_normalized/__init__.py
@@ -1,3 +1,5 @@
+import functools
+
 import event_model
 import pymongo
 from ._version import get_versions
@@ -156,10 +158,7 @@ def _insert(self, name, doc):
                 ) from err
             else:
                 doc.pop("_id")
-                if name == "datum":
-                    id_name = "datum_id"
-                else:
-                    id_name = "uid"
+                id_name = unique_id_name(name)
                 existing = self._collections[name].find_one(
                     {id_name: doc[id_name]}, {"_id": False}
                 )
@@ -171,6 +170,32 @@ def _insert(self, name, doc):
                         f"Existing document:\n{existing}\nNew document:\n{doc}"
                     ) from err
 
+    def _insert_many(self, name, docs):
+        """Bulk write the documents for fewer network requests."""
+        try:
+            self._collections[name].insert_many(docs)
+        except pymongo.errors.BulkWriteError as err:
+            DUPLICATE_KEY_ERROR = 11000
+            duplicate_docs = (
+                error["op"] for error in err.details["writeErrors"]
+                if error["code"] == DUPLICATE_KEY_ERROR
+            )
+            id_name = unique_id_name(name)
+            duplicate_ids = set(
+                doc[id_name] for doc in duplicate_docs
+            )
+            if duplicate_ids:
+                error_message = "\n".join((
+                    "A document with the same unique id as this one "
+                    f"already exists in the database. Document:\n{doc}"
+                    for doc in docs
+                    if doc[id_name] in sorted(duplicate_ids)
+                ))
+                raise DuplicateUniqueID(error_message) from err
+            else:
+                # For example, a "write concern" error
+                raise err
+
     def update(self, name, doc):
         """
         Update documents. Currently only 'start' documents are supported.
@@ -259,29 +284,33 @@ def event(self, doc):
         self._insert("event", doc)
 
     def event_page(self, doc):
-        # Unpack an EventPage into Events and do the actual insert inside
-        # the `event` method. (This is the oppose what DocumentRouter does by
-        # default.)
-
-        event_method = self.event  # Avoid attribute lookup in hot loop.
-        filled_events = []
-
-        for event_doc in event_model.unpack_event_page(doc):
-            filled_events.append(event_method(event_doc))
+        """Unpack an EventPage into Events and do a bulk insert."""
+        event_docs = tuple(
+            event_doc for event_doc in event_model.unpack_event_page(doc)
+        )
+        try:
+            self._insert_many("event", event_docs)
+        except DuplicateUniqueID:
+            # Bulk writing the Events failed; retry inserting each Event
+            event_method = self.event  # Avoid attribute lookup in hot loop.
+            for event_doc in event_docs:
+                event_method(event_doc)
 
     def datum(self, doc):
         self._insert("datum", doc)
 
     def datum_page(self, doc):
-        # Unpack an DatumPage into Datum and do the actual insert inside
-        # the `datum` method. (This is the oppose what DocumentRouter does by
-        # default.)
-
-        datum_method = self.datum  # Avoid attribute lookup in hot loop.
-        filled_datums = []
-
-        for datum_doc in event_model.unpack_datum_page(doc):
-            filled_datums.append(datum_method(datum_doc))
+        """Unpack a DatumPage into 'Datum's and do a bulk insert."""
+        datum_docs = tuple(
+            datum_doc for datum_doc in event_model.unpack_datum_page(doc)
+        )
+        try:
+            self._insert_many("datum", datum_docs)
+        except DuplicateUniqueID:
+            # Bulk writing the 'Datum's failed; retry inserting each Datum
+            datum_method = self.datum  # Avoid attribute lookup in hot loop.
+            for datum_doc in datum_docs:
+                datum_method(datum_doc)
 
     def stop(self, doc):
         self._insert("stop", doc)
@@ -295,6 +324,17 @@ def __repr__(self):
         )
 
 
+@functools.lru_cache(maxsize=16)
+def unique_id_name(name: str) -> str:
+    """Return the name of the unique id field for a named document type."""
+    if name == "datum":
+        id_name = "datum_id"
+    else:
+        id_name = "uid"
+
+    return id_name
+
+
 def _get_database(uri, tls):
     if not pymongo.uri_parser.parse_uri(uri)["database"]:
         raise ValueError(