Due to high demand, the phone lines to the Ticket Office will be open for Season Card sales on Saturday March 6, from 10am-2pm.
The number to dial is 01642 929421, with calls charged at your local call rate.
The Ticket Office phone lines will be closed on Sunday, but supporters can renew or purchase online at tickets.mfc.co.uk
Please note that in line with government guidance, the Ticket Office at the Riverside Stadium remains closed to in-person visitors at the moment.
For more ways to buy your Season Card, including postal applications, visit our How To Buy section.
Season Card holders for the current campaign will see their Season Card automatically roll over for the coming 2021/22 campaign.
And on Tuesday, we opened the Early Bird window, with prices for both 2019/20 Season card holders who chose not to renew for this season, and new applicants.
It's been a busy first week of sales already, particularly after manager Neil Warnock himself committed to the club for the 2021/22 campaign.
And many supporters are following the Boro boss' call to return to the Riverside as Season Card holders, with almost half of purchases so far coming from new applicants.
The Early Bird period for 2019/20 renewals and new purchases runs until 5pm on March 31.