The blaze broke out at around 10 pm at My Tan fishing port in Vinh Hai Commune, according to local fire and rescue police.
Firefighters deployed a fire engine, a water tanker and 10 personnel to the scene, where flames had already engulfed the two vessels anchored more than 150 metres from shore.
Emergency crews worked with local fishermen to contain and extinguish the fire.
Images from the scene showed extensive damage to property on board the boats.
Authorities are investigating the cause of the fire.
