It is due to the ongoing pandemic and requirements for social distancing
Even more events in Plymouth have been postponed until next year.
Britain's Ocean City Running Festival will now take place on Sunday 16 May 2021.
That includes the Half Marathon, 10k and 5k.
The decision to postpone has been made due to the coronavirus pandemic and requirements for social distancing.
A survey by Run Plymouth also found that almost half of all participating runners would not feel safe taking part in the event on its originally scheduled date of 4 October.
All participating runners have been contacted by email and will be able to defer their entries to next year.
For updates about next year's events, please see www.runplymouth.co.uk.