diff --git a/tests/runtime/out_kinesis.c b/tests/runtime/out_kinesis.c
index da3e925a0f8..c8e44a4c874 100644
--- a/tests/runtime/out_kinesis.c
+++ b/tests/runtime/out_kinesis.c
@@ -188,6 +188,110 @@ void flb_test_firehose_nonsense_error(void)
     unsetenv("TEST_PUT_RECORDS_ERROR");
 }
 
+void flb_test_kinesis_default_port(void)
+{
+    int ret;
+    flb_ctx_t *ctx;
+    int in_ffd;
+    int out_ffd;
+    struct flb_output_instance *out;
+
+    /* mocks calls- signals that we are in test mode */
+    setenv("FLB_KINESIS_PLUGIN_UNDER_TEST", "true", 1);
+
+    ctx = flb_create();
+    TEST_CHECK(ctx != NULL);
+
+    in_ffd = flb_input(ctx, (char *) "lib", NULL);
+    TEST_CHECK(in_ffd >= 0);
+    flb_input_set(ctx, in_ffd, "tag", "test", NULL);
+
+    out_ffd = flb_output(ctx, (char *) "kinesis_streams", NULL);
+    TEST_CHECK(out_ffd >= 0);
+    flb_output_set(ctx, out_ffd, "match", "*", NULL);
+    flb_output_set(ctx, out_ffd, "region", "us-west-2", NULL);
+    flb_output_set(ctx, out_ffd, "stream", "fluent", NULL);
+    flb_output_set(ctx, out_ffd, "time_key", "time", NULL);
+
+    /* Start the engine */
+    ret = flb_start(ctx);
+    TEST_CHECK(ret == 0);
+
+    /* Get the output instance */
+    out = flb_output_get_instance(ctx->config, out_ffd);
+    TEST_CHECK(out != NULL);
+
+    /* Check if the port is set to the default value */
+    const char* port = flb_output_get_property("port", out);
+    TEST_CHECK(port == NULL || strcmp(port, "443") == 0);
+    TEST_MSG("Default port should be 443 or not set, but got %s", port ? port : "NULL");
+
+    flb_stop(ctx);
+    flb_destroy(ctx);
+}
+
+
+void flb_test_kinesis_custom_port(void)
+{
+    int ret;
+    flb_ctx_t *ctx;
+    int in_ffd;
+    int out_ffd;
+
+    /* mocks calls- signals that we are in test mode */
+    setenv("FLB_KINESIS_PLUGIN_UNDER_TEST", "true", 1);
+
+    ctx = flb_create();
+
+    in_ffd = flb_input(ctx, (char *) "lib", NULL);
+    TEST_CHECK(in_ffd >= 0);
+    flb_input_set(ctx, in_ffd, "tag", "test", NULL);
+
+    out_ffd = flb_output(ctx, (char *) "kinesis_streams", NULL);
+    TEST_CHECK(out_ffd >= 0);
+    flb_output_set(ctx, out_ffd, "match", "*", NULL);
+    flb_output_set(ctx, out_ffd, "region", "us-west-2", NULL);
+    flb_output_set(ctx, out_ffd, "stream", "fluent", NULL);
+    flb_output_set(ctx, out_ffd, "time_key", "time", NULL);
+    flb_output_set(ctx, out_ffd, "port", "8443", NULL);
+    flb_output_set(ctx, out_ffd, "Retry_Limit", "1", NULL);
+
+    ret = flb_start(ctx);
+    TEST_CHECK(ret == 0);
+
+    flb_stop(ctx);
+    flb_destroy(ctx);
+}
+
+void flb_test_kinesis_invalid_port(void)
+{
+    int ret;
+    flb_ctx_t *ctx;
+    int in_ffd;
+    int out_ffd;
+
+    /* mocks calls- signals that we are in test mode */
+    setenv("FLB_KINESIS_PLUGIN_UNDER_TEST", "true", 1);
+
+    ctx = flb_create();
+
+    in_ffd = flb_input(ctx, (char *) "lib", NULL);
+    TEST_CHECK(in_ffd >= 0);
+    flb_input_set(ctx, in_ffd, "tag", "test", NULL);
+
+    out_ffd = flb_output(ctx, (char *) "kinesis_streams", NULL);
+    TEST_CHECK(out_ffd >= 0);
+    flb_output_set(ctx, out_ffd, "match", "*", NULL);
+    flb_output_set(ctx, out_ffd, "region", "us-west-2", NULL);
+    flb_output_set(ctx, out_ffd, "stream", "fluent", NULL);
+    flb_output_set(ctx, out_ffd, "port", "99999", NULL);  // Invalid port
+
+    ret = flb_start(ctx);
+    TEST_CHECK(ret != 0);  // Expect failure
+
+    flb_stop(ctx);
+    flb_destroy(ctx);
+}
 
 /* Test list */
 TEST_LIST = {
@@ -196,5 +300,8 @@ TEST_LIST = {
     {"throughput_error", flb_test_firehose_throughput_error },
     {"unknown_error", flb_test_firehose_error_unknown },
     {"nonsense_error", flb_test_firehose_nonsense_error },
+    {"default_port", flb_test_kinesis_default_port },
+    {"custom_port", flb_test_kinesis_custom_port },
+    {"invalid_port", flb_test_kinesis_invalid_port },
     {NULL, NULL}
 };