Thailand has no military power to do that.
Not only that, but they are suffering from compatibility and operational issues regarding the 2 Type 053 frigates they received from China. On an operational side, the Thai Navy lacks any submarine force or any viable ASW capability. The Vietnamese Navy could be capable of neutralizing them. In addition their only carrier, the HTMS Chakri Nareubet is under funded and lacks any solid air support. It would be a sitting duck for the Vietnamese Navy.