This is the terrifying moment a speedboat battles rough seas off the coast of Phuket in southern Thailand.

Footage captured by Nat Rakharb shows violent waves pounding the watercraft as it lurches in the choppy waters on July 20.

The captain skillfully navigates through the stormy conditions, keeping the vessel and its passengers safe.

Nat said: 'This is friendship at sea. When there are waves, we will never abandon each other.'

Phuket is among the coastal provinces in Thailand currently being pummelled by heavy rain and stormy seas brought on by Typhoon Wipha.

In neighbouring Vietnam, a tourist boat was capsized by the storm, leaving dozens of passengers dead. The vessel reportedly overturned after being hit by choppy waves and heavy rain off the coast of Ha Long Bay shortly after 2 pm local time.

The Thai Meteorological Department predicted more heavy rain and high seas until July 24. It added that around half of Thailand will be battered with increased rainfall due to the typhoon, which made landfall in China's southern Guangdong province on July 20.

Wipha has been downgraded to a tropical storm after hitting mainland China.