| Club name | Home town | Position | Notes |
| Cobaltore Onagawa | Onagawa, Miyagi | RPS 1st | Promoted from TSL after 1st place in 41st Regional Promotion Series |
| FC Imabari | Imabari, Ehime | 6th | J.League 100 Year Plan club status and J3 license holders |
| All cities/towns in Osaka | 4th | |
| Honda FC | Hamamatsu, Shizuoka | 1st | Defending champions of 2017 |
| Miyazaki, Miyazaki | 8th | |
| Maruyasu Okazaki | Okazaki, Aichi | 9th | |
| MIO Biwako Shiga | Kusatsu, Shiga | 13th | |
| Nara Club | All cities/towns in Nara | 7th | J.League 100 Year Plan club status and J3 license holders |
| Aomori, Aomori | 2nd | |
| Ryūgasaki, Ibaraki | 10th | |
| Sony Sendai | Tagajō, Miyagi | 3rd | |
| Tegevajaro Miyazaki | Miyazaki, Miyazaki | RPS 2nd | Promoted from KSL after 2nd place in 41st Regional Promotion Series |
| Tokyo Musashino City | Musashino, Tokyo | 11th | J.League 100 Year Plan club status |
| Vanraure Hachinohe | Eastern cities/towns in Aomori | 5th | J.League 100 Year Plan club status and J3 license holders |
| Veertien Mie | All cities/towns in Mie | 12th | |
| Verspah Oita | Yufu & Ōita, Ōita | 14th | |