Fort Chulachomklao

Fort Chulachomklao guards the mouth of the Chao Phraya River in Samut Prakan, built under King Chulalongkorn (Rama V) as part of the coastal defences protecting Bangkok from naval attack. Entry is free, open daily 08:00-18:00, and the grounds hold the preserved warship HTMS Maeklong — the longest-serving vessel in Royal Thai Navy history, in service for around 60 years before being decommissioned and set permanently in concrete here as a museum ship.

The site is laid out in five parts: a monument to Rama V, a battery of “Seua Mob” (“crouching tiger”) guns, the HTMS Maeklong museum ship itself, an open-air park of artillery pieces, and a mangrove nature trail along the riverbank. The Seua Mob guns are the fort’s most historically loaded exhibit — seven British-made Armstrong 6-inch “disappearing” cannons, loaded behind cover and raised hydraulically to fire, that opened up on French warships forcing the river mouth on 13 July 1893 during the Paknam Incident. From the museum ship’s deck and the elevated gun positions, the view opens onto the river traffic below: cargo vessels, longtail boats, and fishing craft working the channel where the Chao Phraya meets the Gulf of Thailand.

The mangrove trail is the quieter half of the visit — a short boardwalk loop away from the artillery displays, useful if you want a break from reading plaques. Weekends bring more Thai families and school groups; a weekday morning gets you the fort largely to yourself.

Insider Tip: Climb aboard the HTMS Maeklong itself rather than just viewing it from the pier — the engine room and gun deck are open to walk through, and it’s the single best-preserved exhibit on site.

Watch out: There’s limited shade across the open artillery park, and the riverside location means full sun for a stretch of the walk — bring water and a hat if visiting midday.

Fort Chulachomklao sits a short drive from other Samut Prakan sights, including the Naval Museum and the nearby Phlaeng Faifa Fort, making it easy to combine into a half-day military-history loop along the river.