The first was Tracey Ann Walton, 51, who collapsed and died in her room at the Patong Beach Resort at about 2:10 am.
A friend travelling with her told police that Ms Walton suffered from diabetes and high blood pressure.
Her body was taken to Patong Hospital to confirm the cause of death.
At about 5am 28-year-old Australian Tristan Sheridan apparently lost control of his rented Honda Zoomer X motorcycle and hit a power pole on Ratchapratanusorn Rd near the Patong Municipality Offices.
Rescue volunteers, called to the scene by a passer-by, found Mr Theridan lying in a pool of blood with severe head injuries, but still alive.
He was taken first to Patong Hospital and then transferred to Vachira Phuket Hospital, where he later died of his injuries.