Sukhumvit Road begins in Bangkok, as a continuation of Rama I and Phloen Chit roads which span Pathum Wan district. Starting from where the boundaries of the districts of Khlong Toei, Pathum Wan and Watthana meet, it runs the entire length of the border between Khlong Toei and Watthana, then passes through Phra Khanong and Bang Na districts.
It then crosses the border between Bangkok and Samut Prakan Province and subsequently continues east through Chachoengsao Province, south through Chonburi Province, east through Rayong Province, south-east through Chanthaburi Province, and ends in the town of Trat, capital of Trat Province, about 100km short of the Hat Lek border crossing with Cambodia.
In Chonburi Province it passes through the towns of Chon Buri City, Laem Chabang, Bang Lamung township, Sri Racha, and Pattaya.
In the capital, Sukhumvit Road serves as a main commercial street, and this section is often congested, even at late evening hours. The Chalerm Mahanakhon Expressway has an exit at Soi 1. Ratchadaphisek Road crosses Sukhumvit at the Asok (Asoke) intersection.
The Sukhumvit area of Bangkok is easily accessible on the Skytrain Sukhumvit Line, which runs from Mo Chit through the Silom Line interchange at Siam Square up to On Nut on Soi (side-street) 81. The Bangkok Metro's Sukhumvit Station interchanges with the Skytrain at Asok.
The Sois are numbered from West to East, with odd numbers branching off North-East of Sukhumvit, and even numbers branching off South-West.
The area between Sukhumvit Soi 1 and Sukhumvit Soi 63 is popular as residential area for western expatriates. Japanese nationals tend to prefer from Soi 21 Asok intersection upwards, especially Soi Thong Lo. Rentals tend to be higher in the even numbered streets between Soi 8 and Soi 28 and in the odd numbered streets between Soi 15 and Soi 39. Soi 12 is occupied mainly by Indian expatriates, see Phahurat.
The areas of Soi Cowboy (between Soi 21 Asok and Soi 23) and Nana Entertainment Plaza (Soi 4) are packed full of go-go bars and other places of prostitution. Restaurants of various levels of luxury exist all along the road, as well as hotels including famous names such as The Westin, JW Marriott and Sheraton. Also several shopping malls are found, like the upscale The Emporium shopping center. It also harbours the eastern bus station at Soi 63 Ekkamai.