PTT Forest Station 

The Forest Station is a natural green space unnaturally conceived. It’s 12 rai of wasteland off Sukhaphiban 2 Rd. have been rehabilitated, a human corrective to the man-made problem of environmental degradation. This is especially significant given that the patron of Forest Station is PTT, Thailand’s state-owned oil and gas behemoth. PTT commissioned Japanese botanist and plant ecologist Akira Miyawaki to return the land to Bangkok's original lushy forested state. To this end, Miyawaki brought in 270 varieties of plants native to the ecosystem such as teak, Siamese rosewood and ormosia. The result is a self-sustaining, flourishing and dense jungle—a far cry from the picnic-ready lawns of Lumphini Park. The main attraction is a floating wooden walkway that snakes through the property and offers a canopy view of the beautiful forest.
Sukhaphiban 2 Rd.

Chulalongkorn University 

Downtown’s little-known secret is now out: the breezy, tree-lined lanes of Thailand’s oldest university are open to the public. Stroll through the 595-rai campus that’s boxed between Henri Dunant and Phayathai Roads, read in the shade of a hundred-year-old rain tree (also the university’s symbol) or walk the large lawn in front of the Faculty of Architecture. During March and April, the blossoming bauhinias color the campus pink, an Instagram-worthy phenomenon in itself, but wait for the flowers to drop and you’ll find stretches of walkway briefly carpeted in petals. Architecture enthusiasts will love the hundred-year-old Thai buildings, registered by the Department of Fine Arts as national assets. All the walking should whet your appetite, so head toward the university’s canteen, housed in the Faculty of Arts, where you’ll find decently portioned and delicious food-court fare under B40, such as fried chicken with sticky rice or a bowl of noodles. The iced lattes at True Coffee are also student prices (B70-80 compared to the usual B100+). As a bonus, the university also owns the nearby Park at Siam in the heart of Siam Square. The fun-sized (i.e. miniature) park’s perfect for a brief back-to-nature break if you’ve spent the last hour elbowing out of the crowds thronging Paragon. It has a beautiful, hundred-year-old banyan tree, and beside the gate is a cute greenhouse occupied by Amazon Cafe, should you need a caffeine boost to go with your park-sit. Arrive at the cafe early on weekends or you’ll likely find yourself boxed out by industrious students wielding hefty textbooks.
Phaya Thai Rd. BTS Siam

CU Centenary Park 

Chulalongkorn University’s CU Centenary Park officially opened in March under the auspices of HRH Princess Maha Chakri Sirindhorn. The 30-rai split-story green space celebrates the university’s 100-year anniversary, and is the centerpiece for a huge redevelopment of the 290-rai Samyan neighborhood, stretching from National Stadium to Rama IV Road, which aims to create Bangkok’s very own mini Silicon Valley—a “smart city” home to innovation and startup businesses. In the details, the park has a specially designed wetland with a rain garden, big pond and underground water drainage system. Also, there’s a green bike lane flanked by tropical trees on Chula Soi 5 that links two thoroughfares—
Rama 1 Rd. and Rama 4 Rd.
Bantad Thong Rd. MRT Sam Yan

Kasetsart University  

A 15-minute taxi ride from BTS Mo Chit will land you at one of Bangkok’s largest green spaces, Kasetsart University. Originally founded in 1943 to promote the study of agriculture and natural resources in Thailand, Kasetsart University has held true to its nature-loving mission by cultivating a dense and lush landscape that’s open to outsiders. The 846-rai campus stretches from Vibhavadi-Rangsit Rd. to Ngam Womgwan Rd., and also has a recreational bike lane and a beautiful pond. In the spirit of the university’s founding mission, new students are welcomed with an annual, nonsi tree planting ceremony. 
Vibhavadi-Rangsit Rd. BTS Mo Chit.

Suan Pa Benjakitti (Benjakitti Forest Park)

The picturesque green space and lake next to Queen Sirikit Convention Center welcomes scores of runners, bikers and picnicers daily. But unknown to many is the second, huge park secreted away in the back. Dubbed Suan Pa Benjakitti (Benjakitti Forest Park), this extension of the original park has been unofficially open since August 2016. Visitors can access the park by walking through the carpark of Benjakitti Park and through Gate 2, where you'll find a metal fence guarding another massive (but empty) car park. Keep walking and you'll find a huge sign marking the entrance of Suan Pa Benjakitti. Much as its name suggests, the 61-rai space is home to clusters of trees organized in blocks to create small forests. Around these blocks, a concrete path provides space for runners and bikers. There is also a space dedicated to representative trees from every city in Thailand, with informative signage about their origin and importance. The vast area, owned by the Thailand Tobacco Monopoly, totals 450 rai and had been earmarked to become a public park since the company agreed to move its headquarters to Rojana Industrial Park in Ayutthaya back in 1991. In 1992, 130 rai of the land (though now mostly water) was turned into the current Benjakitti Park. The introduction of the 61-rai Benjakitti Forest Park is the beginning of a three-phase plan to further transform the remaining land. Phase 2 will see the addition of another 170 rai of greenery, and Phase 3 a further 89 rai anicipated to open by 2020.
Ratchadapisek Rd. MRT Queen Sirikit Convention Center 

Phumirak Park Nonthaburi 

Not far from the Phra Nangklao Bridge station of the MRT’s Purple Line is this large, airy park. Funded by the Thai Treasury Department and PTT, it was one of five developments planned 19 years ago in celebration of the sixtieth anniversary of the late King Bhumibol’s reign. The park covers 10 rai on the west bank of the Chao Phraya River and houses the Chalerm Phrakiat Worraviharn Temple, an iconic white pagoda built during the reign of King Rama III. Keep an eye out for the ostentatious, roving peacocks, the pets of the temple’s resident monks. For a more scenic, hour-long journey, take a northbound express Chao Phraya boat from Saphan Taksin pier to Nonthaburi Pibul 3. Here, catch another ferry to cross the river, alighting at the Bang Srimuang pier and the park’s entrance.
Soi Wat Chalerm Phrakiat, Nonthaburi. MRT Saphan Phra Nangklao

Four ideas for bike rides around Bangkok

Beung Makhamted and Beung Sakae Ngarm

These reservoirs in the Min Buri area collect water from Saen Saep and Hok Wa canals. The surrounding area has been developed into a beautiful 4.2km bike route that takes around 30 minutes to complete. Along this route, you will also have herds of cows and buffaloes as cute roadside companions. 
Part of Waree Phirom Park, Pracha Ruam Chai Soi 47 

Bhumibol Bridge

To the southern Bangkok, you’ll find a large area suited to bi`king around Bhumibol Bridge. The route connects three sections along the Chao Phraya River, starting from Yannawa on the Phranakorn side and Puchao Saming Prai in Samut Prakarn to Suksawat on the Thonburi side. The route is most scenic at dusk. 
Wongwaen Utsahakam Rd.

Peppermint Bike Park

This property on Kaset-Nawamin Road is owned by the company that produces the inhalant of the same name, who’ve transformed the 7.5-rai space into a bike lane comprising hilly parts, wooden bridges and obstacles that make your ride more exciting. Entry is B200. 
Yothin Phatthana Soi 3. Open Tue-Fri 4pm-10pm, Sat-Sun 7am-10pm

Route to Ayutthaya

Try taking a day-long bike tour with Spice Roads, who challenge bikers on a 75km route from Bangkok to Ayutthaya’s Wat Chaiwattanaram, a UNESCO World Heritage site, while passing through canals, villages and paddy fields. The tour costs B3,950/head, with bikes included.