diff --git a/esphome/components/api/proto.cpp b/esphome/components/api/proto.cpp
index 4f0d0846d7f..b496ad51108 100644
--- a/esphome/components/api/proto.cpp
+++ b/esphome/components/api/proto.cpp
@@ -48,14 +48,14 @@ uint32_t ProtoDecodableMessage::count_repeated_field(const uint8_t *buffer, size
         }
         uint32_t field_length = res->as_uint32();
         ptr += consumed;
-        if (ptr + field_length > end) {
+        if (field_length > static_cast<size_t>(end - ptr)) {
           return count;  // Out of bounds
         }
         ptr += field_length;
         break;
       }
       case WIRE_TYPE_FIXED32: {  // 32-bit - skip 4 bytes
-        if (ptr + 4 > end) {
+        if (end - ptr < 4) {
           return count;
         }
         ptr += 4;
@@ -110,7 +110,7 @@ void ProtoDecodableMessage::decode(const uint8_t *buffer, size_t length) {
         }
         uint32_t field_length = res->as_uint32();
         ptr += consumed;
-        if (ptr + field_length > end) {
+        if (field_length > static_cast<size_t>(end - ptr)) {
           ESP_LOGV(TAG, "Out-of-bounds Length Delimited at offset %ld", (long) (ptr - buffer));
           return;
         }
@@ -121,7 +121,7 @@ void ProtoDecodableMessage::decode(const uint8_t *buffer, size_t length) {
         break;
       }
       case WIRE_TYPE_FIXED32: {  // 32-bit
-        if (ptr + 4 > end) {
+        if (end - ptr < 4) {
           ESP_LOGV(TAG, "Out-of-bounds Fixed32-bit at offset %ld", (long) (ptr - buffer));
           return;
         }