The accident happened on the Phang Nga-Takua Thung section of Phetkasem Road in Takua Thung district shortly after the bus left the Ayothaya Hotel in Krabi at 5am.
The tourists booked with CNR Travel were heading to the Ban Tha Noon Pier.
The impact shattered the utility pole, with the upper part in turn striking the front of the bus, ripping a role across half the roof.
Driver Arkom Daengnam, 40, died at the wheel. Four of the 19 passengers were severely injured, said police, who suspectt the driver dozed off and lost control.