diff --git a/tests/components/packet_transport/binary_sensor/binary_sensor_test.cpp b/tests/components/packet_transport/binary_sensor/binary_sensor_test.cpp
index 36af087d2c2..5ad25c2d7d1 100644
--- a/tests/components/packet_transport/binary_sensor/binary_sensor_test.cpp
+++ b/tests/components/packet_transport/binary_sensor/binary_sensor_test.cpp
@@ -5,6 +5,7 @@ namespace esphome::packet_transport::testing {
 TEST(PacketTransportBinarySensorTest, AddBinarySensor) {
   TestablePacketTransport transport;
   binary_sensor::BinarySensor bs;
+  transport.set_binary_sensor_count(1);
   transport.add_binary_sensor("motion", &bs);
   ASSERT_EQ(transport.binary_sensors_.size(), 1u);
   EXPECT_STREQ(transport.binary_sensors_[0].id, "motion");
@@ -24,6 +25,7 @@ TEST(PacketTransportBinarySensorTest, UnencryptedBinarySensorRoundTrip) {
   encoder.init_for_test("sender");
   binary_sensor::BinarySensor local_bs;
   local_bs.state = true;
+  encoder.set_binary_sensor_count(1);
   encoder.add_binary_sensor("motion", &local_bs);
 
   encoder.send_data_(true);
@@ -46,11 +48,13 @@ TEST(PacketTransportBinarySensorTest, MultipleSensorsRoundTrip) {
   sensor::Sensor s1, s2;
   s1.state = 10.0f;
   s2.state = 20.0f;
+  encoder.set_sensor_count(2);
   encoder.add_sensor("s1", &s1);
   encoder.add_sensor("s2", &s2);
 
   binary_sensor::BinarySensor bs1;
   bs1.state = true;
+  encoder.set_binary_sensor_count(1);
   encoder.add_binary_sensor("bs1", &bs1);
 
   encoder.send_data_(true);
diff --git a/tests/components/packet_transport/sensor/sensor_test.cpp b/tests/components/packet_transport/sensor/sensor_test.cpp
index 2f681aee587..5d1cfb4bc2b 100644
--- a/tests/components/packet_transport/sensor/sensor_test.cpp
+++ b/tests/components/packet_transport/sensor/sensor_test.cpp
@@ -5,6 +5,7 @@ namespace esphome::packet_transport::testing {
 TEST(PacketTransportSensorTest, AddSensor) {
   TestablePacketTransport transport;
   sensor::Sensor s;
+  transport.set_sensor_count(1);
   transport.add_sensor("temp", &s);
   ASSERT_EQ(transport.sensors_.size(), 1u);
   EXPECT_STREQ(transport.sensors_[0].id, "temp");
@@ -26,6 +27,7 @@ TEST(PacketTransportSensorTest, UnencryptedSensorRoundTrip) {
   encoder.init_for_test("sender");
   sensor::Sensor local_sensor;
   local_sensor.state = 42.5f;
+  encoder.set_sensor_count(1);
   encoder.add_sensor("temp", &local_sensor);
 
   encoder.send_data_(true);
@@ -53,6 +55,7 @@ TEST(PacketTransportSensorTest, EncryptedSensorRoundTrip) {
   encoder.set_encryption_key(key);
   sensor::Sensor local_sensor;
   local_sensor.state = 99.9f;
+  encoder.set_sensor_count(1);
   encoder.add_sensor("temp", &local_sensor);
 
   encoder.send_data_(true);
@@ -77,6 +80,7 @@ TEST(PacketTransportSensorTest, SendDataOnlyUpdated) {
   sensor::Sensor s1, s2;
   s1.state = 1.0f;
   s2.state = 2.0f;
+  encoder.set_sensor_count(2);
   encoder.add_sensor("s1", &s1);
   encoder.add_sensor("s2", &s2);
 
@@ -111,6 +115,7 @@ TEST(PacketTransportSensorTest, PingKeyIncludedInTransmittedPacket) {
   responder.set_encryption_key(key);
   sensor::Sensor local_sensor;
   local_sensor.state = 77.7f;
+  responder.set_sensor_count(1);
   responder.add_sensor("temp", &local_sensor);
 
   // Requester sends a MAGIC_PING that the responder processes
@@ -148,6 +153,7 @@ TEST(PacketTransportSensorTest, MissingPingKeyBlocksSensorData) {
   responder.set_encryption_key(key);
   sensor::Sensor local_sensor;
   local_sensor.state = 77.7f;
+  responder.set_sensor_count(1);
   responder.add_sensor("temp", &local_sensor);
   responder.send_data_(true);
   ASSERT_EQ(responder.sent_packets.size(), 1u);