The Ancient City in Samut Prakan
The easiest, nearest option on this list of Bangkok day trips definitely doesn’t require an overnight stay. The Ancient City (also commonly called "Ancient Siam") is just about an hour away. If you only have an afternoon to spare and want to get away from Bangkok’s concrete embrace, head an hour south for a pleasant escape.
Wandering the beautifully manicured 200 acres of the Ancient City provides a microcosm of Thai culture and history. The atmosphere is romantic. Famous archaeological sites—some of which are difficult to reach or no longer standing—have been tastefully recreated. Photogenic monuments, temple replicas, Buddha statues, and gardens provide a peaceful respite from the city along with a chance to learn a bit about Thailand. In fact, the entire park is actually shaped like Thailand.
The grounds are expansive, so if the walking is too much, bicycles and golf carts can be rented. Guided tram tours are available. The relatively steep entrance fee of 700 baht (around $22) is cut in half at 4 p.m. The Ancient City closes at 7 p.m.
To get there, bypass some of Bangkok’s perpetual traffic jam along Sukhumvit by taking the Skytrain to On Nut station. Try not to laugh about the name, then switch to a taxi or Grab (Bangkok's equivalent of Uber). Tell the driver you want to visit the Ancient City (Muang Boran).
Ayutthaya
Although Ayutthaya, the ancient capital of Siam from 1350 to 1767, is often visited as a day trip from Bangkok, an optional overnight stay will provide proper time to enjoy.
On a day trip, you’ll be rushed trying to see so many ruins in a single afternoon and ultimately miss the ancient vibe that permeates the place. The Burmese sacked the old capital in 1767, causing it to be moved downriver to where Bangkok stands today.
The crumbling temples and headless Buddha statues of Ayutthaya (properly pronounced "ai-yoot-tai-yah") are best enjoyed in much the same way as Angkor Wat in Cambodia: by renting a bicycle.
Centuries of Thai history can be absorbed by exploring the many temples, structures, and museums. You may even find yourself alone, awash in archeology, at some of the less popular temple sites.
The best way to get to Ayutthaya is by train. You’ll glide past much of Bangkok’s traffic while enjoying some authentic scenery. Depending on which train service you choose, the journey takes around 2 hours. You can purchase a ticket yourself for one of the many daily trains at the Hualamphong Railway Station.
Kanchanaburi
Located west of Bangkok at the confluence of three rivers, Kanchanaburi is a relatively quick escape from the hectic pace of Thailand’s capital.
But arriving in Kanchanaburi doesn’t feel much more peaceful—at least until you get out of the busy part of the city and choose one of the many guesthouses with pleasant gardens stretched along the river.
The French novel "The Bridge Over the River Kwai" was set in Kanchanaburi. The bridge and most of the story in the film were highly fictionalized. Technically, the bridge in the movie should have been "The Bridge Over the River Mae Klong." And River Kwai should be "Khwae Yai."
Regardless, the important bridge in Kanchanaburi was one of many that were part of the infamous "Death Railway" constructed and repaired by forced POW labor. The infamous "Hellfire Pass" is nearby. World War II history abounds in the area. Visit the museum and one of the war cemeteries to learn the real story.
The cascading waterfalls of nearby Erawan National Park are a great way to forget about how much history and Hollywood often disagree. Plan to cool off in one of the turquoise pools along the hike.
Kanchanaburi can be reached from Bangkok via bus or train; however, buses and mini-buses are the most popular options because trains depart from Thonburi Station, across the Chao Phraya River in the northwest part of Bangkok. The two daily trains take around 3 hours to reach Kanchanaburi. Getting there by bus may take up to 5 hours, depending on traffic and tenacity of your driver.
Koh Samet
At around 4 hours from Bangkok, Koh Samet is just slightly out of day trip range, but that doesn’t stop it from attracting a lot of travelers who would rather spend their last day or two in Thailand on a beach.
Although Koh Samet has all the usual ingredients of a Thai island (beautiful beaches, fire shows, and bucket drinks), it somehow misses the chill vibe that permeates Koh Lanta, Koh Tao, and other islands. Regardless, if you’re short on days before flying out of Bangkok, Koh Samet is an excellent choice for cleaner air and a fire-show cocktail.
The easiest way to get to Koh Samet is to purchase a bus-boat combo ticket, on offer from every travel agent in Bangkok. If you still want to make your own way, get help finding one of the minivans that frequently depart from Victory Monument; they run directly to the ferry pier. Once at the dock, you can purchase your boat ticket for the short hop to the island. Beware: there isn’t much room for luggage in the local minivans.
Koh Si Chang
Not to be confused with the much larger Koh Chang, Koh Si Chang is a small island situated close to Pattaya. Although beaches aren’t as nice due to the rocks and heavy boat traffic, at only 3 hours away or so, it is tantalizingly convenient. The island serves as a weekend getaway for locals who want to be nearer to the sea. Peace prevails on the island, unlike nearby Pattaya.
Koh Si Chang is home to a royal summer palace no longer in use, a small community, temples, and several interesting caves.
Getting to Koh Si Chang requires passing through Sri Racha in Chonburi Province, the namesake of the highly celebrated hot sauce. The trip takes around 3 hours, including an hour on the ferry.
Koh Laan
Often transliterated as “Koh Larn,” Koh Laan (Coral Island) is Koh Si Chang’s little island neighbor to the south. Koh Laan is slightly closer to Pattaya and offers better beaches and sand than those found on the mainland or Koh Si Chang. The island isn’t exactly undeveloped (yes, there is a 7-Eleven); however, the atmosphere is relaxed.
Koh Laan ends up being a quick jaunt for travelers and locals in Pattaya who go over for swimming and seafood. There isn’t much to do on Koh Laan aside from sunbathing, snorkeling, and swimming—but that’s the point!
Ferries from Pattaya take around an hour, or you can cut travel time in half and have more fun by upgrading to a longtail speedboat. Watch out for the resident monkeys on the island; they’ve been known to rob bags left on the beach.