2017 Thai League 3

The 2017 Thai League 3 (known as the Euro Cake League Pro for sponsorship reasons) football season will be the first season of Thai League 3. 29 clubs will be divided into 2 groups (regions).

Upper Region
Promoted from 2016 Regional League Division 2 Northern Division
 * Kamphaeng Phet
 * Phrae United
 * Phayao
 * Lamphun Warrior

Promoted from 2016 Regional League Division 2 North-Eastern Region
 * Udon Thani
 * Ubon Ratchathani
 * Kalasin
 * Khon Kaen
 * Amnat Poly United

Promoted from 2016 Regional League Division 2 Eastern Region
 * Cha Choeng Sao
 * Prachinburi United
 * Sa Kaeo

Promoted from 2016 Regional League Division 2 Central Region
 * Ayutthaya Warrior
 * Ayutthaya
 * Singburi Bang Rachan
 * Ayutthaya United

Lower Region
Promoted from 2016 Regional League Division 2 Bangkok & field Region
 * Chamchuri United
 * BU.Deffo
 * Royal Thai Army

Promoted from 2016 Regional League Division 2 Bangkok & Eastern Region
 * Raj Pracha
 * Customs United
 * Banbung United
 * Kasem Bundit University

Promoted from 2016 Regional League Division 2 Western Region
 * Samut Sakhon
 * Krung Thonburi
 * Ratchaphruek University
 * Simork
 * BTU United

Promoted from 2016 Regional League Division 2 Southern Region
 * Surat Thani
 * Nara United
 * Trang
 * Ranong United

Changed clubs

 * Ayutthaya Warrior was reinstated to Phichit.

Changed name

 * Ratchaphruek University changed to  Nakhon Si Thammarat Unity.

Withdrawn clubs

 * Prachinburi United and BTU United have withdrawn from the 2017 campaign due to club licensing problems.
 * Phichit

Third place play-off
This round was featured by Udon Thani, the second place of 2017 Thai League 3 Upper Region and Trang, the second place of 2017 Thai League 3 Lower Region. Winners of third place play-off would promoted to 2018 Thai League 2.

Matches
''3–3 on aggregate. Udon Thani won on away goals.''

Final
This round was featured by Khonkaen, the first place of 2017 Thai League 3 Upper Region and Samut Sakhon, the first place of 2017 Thai League 3 Lower Region. Both winners and runners-up would promoted to 2018 Thai League 2 automatically.

Matches
Samut Sakhon won 5–2 on aggregate.