The 21-year-old goalkeeper arrives at the club on a season-long loan from Premier League side Watford in July 2021.
Parkes, who will wear the number 20 shirt for manager Andy Hessenthaler’s side this season, has played in the National League previously, playing the final eight games of last season for Barnet.
He kept clean sheets against Sutton United, Maidenhead, and Weymouth in those eight games.
A former England under-17 representative, Parkes joined Watford from Southampton in January 2019.
He had spent 10 years with the Saints before joining the Hornets, where he has been a regular in the under-23s team as well as travelling with the first-team squad and appearing on the bench during Watford’s successful promotion-winning campaign last season.