Submission Underground 18 took place Sunday, October 4, 2020 with 10 fights in Portland, Oregon.
| Actor | Role |
|---|---|
 Mason FowlerSelf | Self |
 Vinny MagalhãesSelf | Self |
 Kendall ReusingSelf | Self |
 Leah TaylorSelf | Self |
 William TackettSelf | Self |
| GGabriel CheccoSelf | Self |
 Keith KirkorianSelf | Self |
| RRafael DomingosSelf | Self |
 Kody SteeleSelf | Self |
 Bryan NuroSelf | Self |
 Hunter ColvinSelf | Self |
| EEmil FischerSelf | Self |
| AAaron TiegsSelf | Self |
| AAlex LarmeySelf | Self |
 Andy VarelaSelf | Self |
 Nick RonanSelf | Self |
| AAndrew AlexanderSelf | Self |
 Pablo AlfonsoSelf | Self |
| AAlan SanchezSelf | Self |
| JJustin RenickSelf | Self |