Phra Pathom Chedi in Nakhon Pathom is one of the tallest stupas in the world, about 120 metres high. The town is thought to be where Buddhism first reached Thailand. An older stupa lies inside; King Mongkut, who visited it as a monk, ordered the present one built over it in the 19th century. Its golden-orange tiles shine in the sun, and cloisters with Buddha images surround it.

The Bridge on the River Kwai in Kanchanaburi was part of the Burma Railway, built by the Japanese army in 1942 and 1943 using Allied prisoners of war and Asian labourers. Many thousands died building the line. The steel bridge was bombed in 1945 and later repaired, with square spans replacing the damaged round ones. Trains still cross it, and visitors can walk over it.

The Kanchanaburi War Cemetery holds the graves of nearly 7,000 Allied prisoners of war who died building the Burma Railway. Most were British, Australian and Dutch. It is cared for by the Commonwealth War Graves Commission, with neat rows of bronze plaques set in lawns and flowers. The Thailand-Burma Railway Centre museum stands across the road.

Tham Krasae is a section of the Burma Railway where the line runs along a wooden viaduct built against a cliff above the Kwai Noi River. It was built by prisoners of war in 1943. Trains from Kanchanaburi slow to a crawl as they cross. A small station and a cave with a Buddha image lie beside the track, and visitors can walk along the viaduct between trains.

Hellfire Pass is a deep cutting on the Burma Railway, dug through rock by Allied prisoners of war and Asian labourers in 1943. They worked day and night with simple tools, and the light of fires at night gave the pass its name. Many died here. The Australian government runs a museum at the top, and a walking trail follows the old railway bed.

Erawan National Park lies in the forested hills of Kanchanaburi. It is best known for the Erawan Falls, a stream that drops over seven tiers of limestone into pools of turquoise water. The top tier is said to look like Erawan, the three-headed elephant of Hindu myth. A path climbs about two kilometres past all seven levels, and the pools are good for swimming.

Sai Yok National Park lies along the Kwai Noi River in western Kanchanaburi, near the border with Myanmar. Its best known sight is the Sai Yok Noi waterfall, which tumbles over limestone beside the road. The park has caves, forest trails and floating raft houses on the river. It is also home to the tiny Kitti's hog-nosed bat, one of the smallest mammals in the world.