Ko Phuket (48 km from N to S and 21 km from E to W), which is part of Thailand, in the Andaman sea, is separated from the W coast of the Malay Peninsula by the narrow channel Chong Pak Phra.
Chong Pak Phra has a length of 12 miles and a width of about 0.4 mile at its W entrance. The land on both sides is mostly low and wooded with several villages along both shores of the channel. North of the channel are hills of moderate elevation.

Phuket Island is irregularly shaped, with a length of 26 miles N to S and an average width of 8 miles E to W.

Pantong Bay is located on the W side of the island and Makham Bay is located on the SE side.

The name Phuket is derived from two Thai words, phu (mountain) of ket (jewel).

Tides/Currents:

The flood tide sets in from both ends of Chong Pak Phra and meets about 3 miles E of the W entrance.
The current is weak in the middle of the channel, but at the W entrance, it sometimes attains a rate of 6 knots, and a velocity of 3 knots in the E entrance.

Depths/Limitations:

The depth on the bar at the W entrance to Chong Pak Phra is subject to great changes, varying from 1.8 to 5.5m. During the outhwest Monsoon, the sea breaks across the W entrance, but during the Northeast Monsoon, the water is smooth. Chong Pak Phra should only be used with local knowledge and by small craft. In the E entrance of the strait there are several islets, with the innermost having a height of 92m.

Anchorage:

Good anchorage may be obtained by vessels with local knowledge, inside the bar at the W entrance, in a depth of about 9.1m.

The W side of Ko Phuket is indented by several bays with anchorage depths, but none of these bays afford shelter during the Southwest Monsoon. The N part of this coast except for the first 7 miles, is low and wooded, and the hills immediately within it attain a height of 140 to 258m.

Along the S part of the W coast is a range of densely-wooded mountains, 305 to 559m high, sloping gradually at its N and S ends.