diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index 5f2a90d5472..52e6850b265 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -383,6 +383,22 @@ class ProtoEncode {
   encode_field_raw(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, uint32_t type) {
     return encode_varint_raw(pos PROTO_ENCODE_DEBUG_ARG, proto_tag(field_id, type));
   }
+  /// Write a field key through the local cursor. Sub-message fields commonly have a 2-byte tag.
+  [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
+  write_tag_(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, uint32_t type) {
+    uint32_t tag = proto_tag(field_id, type);
+#ifdef ESPHOME_DEBUG_API
+    return encode_varint_raw(pos PROTO_ENCODE_DEBUG_ARG, tag);
+#else
+    uint8_t *__restrict__ p = pos;
+    while (tag > 0x7F) {
+      *p++ = static_cast<uint8_t>(tag | 0x80);
+      tag >>= 7;
+    }
+    *p++ = static_cast<uint8_t>(tag);
+    return p;
+#endif
+  }
   /// Write a single precomputed tag byte. Tag must be < 128.
   [[nodiscard]] static inline uint8_t *ESPHOME_ALWAYS_INLINE
   write_raw_byte(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM, uint8_t b) {
@@ -568,7 +584,7 @@ class ProtoEncode {
   template<typename T>
   [[nodiscard]] static inline uint8_t *encode_sub_message(uint8_t *__restrict__ pos PROTO_ENCODE_DEBUG_PARAM,
                                                           uint32_t field_id, const T &value) {
-    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 2);
+    pos = write_tag_(pos PROTO_ENCODE_DEBUG_ARG, field_id, WIRE_TYPE_LENGTH_DELIMITED);
     return encode_sub_message_body(pos PROTO_ENCODE_DEBUG_ARG, &value, &T::encode_msg);
   }
   /// Singular sub-message field, skipped when it encodes to nothing.
@@ -578,7 +594,7 @@ class ProtoEncode {
     uint32_t nested_size = T::calc_size_msg(&value);
     if (nested_size == 0)
       return pos;
-    pos = encode_field_raw(pos PROTO_ENCODE_DEBUG_ARG, field_id, 2);
+    pos = write_tag_(pos PROTO_ENCODE_DEBUG_ARG, field_id, WIRE_TYPE_LENGTH_DELIMITED);
 #ifdef ESPHOME_DEBUG_API
     uint8_t *end = encode_sized_sub_message_body(pos PROTO_ENCODE_DEBUG_ARG, nested_size, &value, &T::encode_msg);
     proto_check_sub_message_size(field_id, nested_size, pos, end);