Bangkok Hotel Lotus Sukhumvit - Le Boulanger
Cake Buffet: THB 333 net
http://www.hotellotussukhumvit.com/bangkok-hotel-promotions/
Grand Hyatt Erawan - Erawan Tea Room
Afternoon Tea: THB 650++
http://bangkok.grand.hyatt.com/en/hotel/dining/ErawanTeaRoom.html
Mandarin Oriental - Authors' Lounge
Afternoon Tea Set: Baht 1,500++ per person
http://www.mandarinoriental.com/bangkok/fine-dining/authors-lounge/
Marriott Marquis - The Lobby Lounge
Afternoon tea set: THB 590++ per person
https://www.bangkokmarriottmarquisqueenspark.com/dining/the-lobby-lounge/
Okura Prestige @ Park Ventures Ecoplex - Up & Above Lounge
Afternoon Tea (Daily): Baht 1,290++
http://www.okurabangkok.com/en/hotel-offers-bangkok.html
Park Hyatt Bangkok - Living Room
Afternoon tea (daily): THB 800++ for one, THB 1,500++ for two
https://bangkok.park.hyatt.com/en/hotel/dining/living-room.html
Peninsula - The Lobby
Afternoon Tea: THB 1,400++ per set for two people
http://bangkok.peninsula.com/en/fine-dining/the-lobby-afternoon-tea
Pullman Bangkok King Power - The Junction
Afternoon tea: THB 499 net per set
http://www.pullmanbangkokkingpower.com/bangkok-hotel-promotion-special-offers/
Sheraton Grande Sukhumvit - The Living Room
Afternoon Tea (Mon-Sat): THB 440 for one / 755 for two persons
https://sheratongrandesukhumvit-onlinestore.com
Siam Kempinski - Hanuman Bar
Afternoon Tea: THB 750++ per person
http://www.kempinski.com/en/bangkok/siam-hotel/dining/culinary-highlights/
St. Regis - The Drawing Room & The St. Regis Bar
Thai Afternoon Tea: THB 950++ per set for two person
Western Afternoon Tea: THB 1,500++ per set for two persons
https://www.marriott.com/hotels/hotel-information/restaurant/details-1/bkkxr-the-st-regis-bangkok/
Sukhothai - Lobby Salon
Afternoon Tea (Mon-Thurs): THB 880++ per person
Chocolate Buffet (Fri-Sun): THB 990++ per person
http://www.sukhothai.com/Dining/Salon/
Disclaimer: Please check with the hotels for precise and up-to-date rates.