The champions league round was the next stage from the regional stage of 2018 Thai League 4. The winners of each regions, the runners-up of some regions, and the winners of qualifying play-off would qualified to this round to finding 3 clubs promoting to 2019 Thai League 3.
Teams
Note:
Qualifying play-offs
Upper region
Lower region
Preliminary round
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!colspan=3|Upper region
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!colspan=3|Lower region
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Upper region
Lower region
Play-off round
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!colspan=3|Upper region
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!colspan=3|Lower region
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Upper region
Lower region
Group stage
Upper region
Lower region
Knockout stage
Winners, runners-up, and third place of 2018 Thai League 4 would promoted to 2019 Thai League 3.
Third place play-off
Summary
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Matches
North Bangkok University won 2–1 on aggregate.
Final
Summary
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Matches
Nakhon Pathom United won 5–4 on aggregate.
Teams promoted to 2019 Thai League 3
Nakhon Pathom United (champions) Khon Kaen United (runners-up) North Bangkok University (Third-placed)
Goalscorers
6 goals
Maranhão (North Bangkok University)
5 goals
Jardel Capistrano (Khon Kaen United) Olveira Silva Diego (Nakhon Pathom United) Chamsuddeen Shoteng (Satun United)
4 goals
João Francisco (North Bangkok University) Poomipat Kantanet (North Bangkok University) Martins Caio Henrique (Satun United) Natthawut Munsuwan (Satun United)
3 goals
Chainarong Samuttha (Chanthaburi) Charin Buthad (Khon Kaen United) Chanukun Karin (North Bangkok University) Diop Badara Aly (Yasothon)
2 goals
Kaikitti Inuthen (Bankhai United) Piya Kruawan (Bankhai United) Krittanon Thanachotjareanphon (Grakcu Saimai United) Chatchai Phithanmet (Huahin City) Tebnimit Buransri (Khon Kaen United) Nakun Phintong (Nakhon Pathom United) Pongsathon Tongchaum (Nakhon Pathom United) Pattanapong Chumchan (Yasothon) Vichit Singloilom (Yasothon)
1 goal
Camara Souleymane (Bankhai United) Chokchai Sukthed (Bankhai United) Elvis Job (Bankhai United) Pongrawit Jantawong (BGC) Thammayut Rakbun (BGC) Ozor Enoch (Chanthaburi) Tripop Jaroensheep (Chanthaburi) Rattikun Plonghirun (Grakcu Saimai United) Samart Phetnoo (Grakcu Saimai United) Amorn Mudlied (Hatyai) Anon Kaimook (Huahin City) Panudach Subpeng (Huahin City) Songkran Puangnoy (Huahin City) Kissi Koffi Ludovic Loic (IPE Samut Sakhon United) Pantakan Kasemkulwirai (IPE Samut Sakhon United) Phethai Sa-ngiamsak (IPE Samut Sakhon United) Abass Ouro-Nimini (Muang Loei United) André Houma Ekue (Muang Loei United) Chawin Thirawatsri (Muang Loei United) Krit Phavaputanon (Muang Loei United) Chokchai Chuchai (Nakhon Pathom United) Lesley Ablorh (Nakhon Pathom United) Nattaphon Worasut (Nakhon Pathom United) Saeid Chahjouei (Nakhon Pathom United) Wisarut Pannasi (Nakhon Pathom United) Jettarin Phetborisut (Pluakdaeng Rayong United) Fabricio Marabá (Satun United) Manso Ausman (Satun United) Thanakorn Sathanpong (Satun United) Thirawat Lertpitchapatch (Satun United) Diarra Aboubacar Sidick (Uttaradit) Kritnapop Mekputcharakul (Uttaradit) Patipat Kamsat (Uttaradit) Otis Sarfo Adjei (Yasothon)
Own goal
Tanakit Wonglikit (Bankhai United against Chanthaburi) Panadon Lexsuwan (Chanthaburi against Muang Loei United) Yongyut Jareonpoom (Chanthaburi against Muang Loei United) Chatchai Maneewan (Grakcu Saimai United against Pattani)