diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 1ac5a3aaad..ba904a7f40 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -47,6 +47,7 @@ jobs:
       - uses: nolar/setup-k3d-k3s@v1
         with:
           version: "${{ matrix.kubernetes }}"
+          k3d-tag: v4.4.8
           k3d-args: --no-lb
       - name: Prefetch container images
         run: >
diff --git a/internal/controller/postgrescluster/postgres.go b/internal/controller/postgrescluster/postgres.go
index 78b55d7796..56e03c4077 100644
--- a/internal/controller/postgrescluster/postgres.go
+++ b/internal/controller/postgrescluster/postgres.go
@@ -37,6 +37,7 @@ import (
 	"github.com/crunchydata/postgres-operator/internal/logging"
 	"github.com/crunchydata/postgres-operator/internal/naming"
 	"github.com/crunchydata/postgres-operator/internal/pgaudit"
+	"github.com/crunchydata/postgres-operator/internal/postgis"
 	"github.com/crunchydata/postgres-operator/internal/postgres"
 	pgpassword "github.com/crunchydata/postgres-operator/internal/postgres/password"
 	"github.com/crunchydata/postgres-operator/internal/util"
@@ -188,7 +189,7 @@ func (r *Reconciler) reconcilePostgresDatabases(
 
 	// Calculate a hash of the SQL that should be executed in PostgreSQL.
 
-	var pgAuditOK bool
+	var pgAuditOK, postgisInstallOK bool
 	create := func(ctx context.Context, exec postgres.Executor) error {
 		if pgAuditOK = pgaudit.EnableInPostgreSQL(ctx, exec) == nil; !pgAuditOK {
 			// pgAudit can only be enabled after its shared library is loaded,
@@ -201,6 +202,18 @@ func (r *Reconciler) reconcilePostgresDatabases(
 				"Unable to install pgAudit; try restarting PostgreSQL")
 		}
 
+		// Enabling PostGIS extensions is a one-way operation
+		// e.g., you can take a PostgresCluster and turn it into a PostGISCluster,
+		// but you cannot reverse the process, as that would potentially remove an extension
+		// that is being used by some database/tables
+		if cluster.Spec.PostGISVersion != "" {
+			if postgisInstallOK = postgis.EnableInPostgreSQL(ctx, exec) == nil; !postgisInstallOK {
+				// TODO(benjb): Investigate under what conditions postgis would fail install
+				r.Recorder.Event(cluster, corev1.EventTypeWarning, "PostGISDisabled",
+					"Unable to install PostGIS")
+			}
+		}
+
 		return postgres.CreateDatabasesInPostgreSQL(ctx, exec, databases.List())
 	}
 
@@ -232,7 +245,7 @@ func (r *Reconciler) reconcilePostgresDatabases(
 		log := logging.FromContext(ctx).WithValues("revision", revision)
 		err = errors.WithStack(create(logging.NewContext(ctx, log), podExecutor))
 	}
-	if err == nil && pgAuditOK {
+	if err == nil && pgAuditOK && postgisInstallOK {
 		cluster.Status.DatabaseRevision = revision
 	}
 
diff --git a/internal/postgis/postgis.go b/internal/postgis/postgis.go
new file mode 100644
index 0000000000..b9abec57f0
--- /dev/null
+++ b/internal/postgis/postgis.go
@@ -0,0 +1,53 @@
+/*
+ Copyright 2021 Crunchy Data Solutions, Inc.
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+package postgis
+
+import (
+	"context"
+	"strings"
+
+	"github.com/crunchydata/postgres-operator/internal/logging"
+	"github.com/crunchydata/postgres-operator/internal/postgres"
+)
+
+// EnableInPostgreSQL installs triggers for the following extensions into every database:
+//  - postgis
+//  - postgis_topology
+//  - fuzzystrmatch
+//  - postgis_tiger_geocoder
+func EnableInPostgreSQL(ctx context.Context, exec postgres.Executor) error {
+	log := logging.FromContext(ctx)
+
+	stdout, stderr, err := exec.ExecInAllDatabases(ctx,
+		strings.Join([]string{
+			// Quiet NOTICE messages from IF NOT EXISTS statements.
+			// - https://www.postgresql.org/docs/current/runtime-config-client.html
+			`SET client_min_messages = WARNING;`,
+
+			`CREATE EXTENSION IF NOT EXISTS postgis;`,
+			`CREATE EXTENSION IF NOT EXISTS postgis_topology;`,
+			`CREATE EXTENSION IF NOT EXISTS fuzzystrmatch;`,
+			`CREATE EXTENSION IF NOT EXISTS postgis_tiger_geocoder;`,
+		}, "\n"),
+		map[string]string{
+			"ON_ERROR_STOP": "on", // Abort when any one statement fails.
+			"QUIET":         "on", // Do not print successful statements to stdout.
+		})
+
+	log.V(1).Info("enabled PostGIS and related extensions", "stdout", stdout, "stderr", stderr)
+
+	return err
+}
diff --git a/internal/postgis/postgis_test.go b/internal/postgis/postgis_test.go
new file mode 100644
index 0000000000..d7e09e69ed
--- /dev/null
+++ b/internal/postgis/postgis_test.go
@@ -0,0 +1,54 @@
+/*
+ Copyright 2021 Crunchy Data Solutions, Inc.
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+package postgis
+
+import (
+	"context"
+	"errors"
+	"io"
+	"io/ioutil"
+	"strings"
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestEnableInPostgreSQL(t *testing.T) {
+	expected := errors.New("whoops")
+	exec := func(
+		_ context.Context, stdin io.Reader, stdout, stderr io.Writer, command ...string,
+	) error {
+		assert.Assert(t, stdout != nil, "should capture stdout")
+		assert.Assert(t, stderr != nil, "should capture stderr")
+
+		assert.Assert(t, strings.Contains(strings.Join(command, "\n"),
+			`SELECT datname FROM pg_catalog.pg_database`,
+		), "expected all databases and templates")
+
+		b, err := ioutil.ReadAll(stdin)
+		assert.NilError(t, err)
+		assert.Equal(t, string(b), `SET client_min_messages = WARNING;
+CREATE EXTENSION IF NOT EXISTS postgis;
+CREATE EXTENSION IF NOT EXISTS postgis_topology;
+CREATE EXTENSION IF NOT EXISTS fuzzystrmatch;
+CREATE EXTENSION IF NOT EXISTS postgis_tiger_geocoder;`)
+
+		return expected
+	}
+
+	ctx := context.Background()
+	assert.Equal(t, expected, EnableInPostgreSQL(ctx, exec))
+}