Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Grimsby to Plymouth as you normally would.
Located just 11.0 mi from the city centre, Grimsby Humberside is the airport most travellers will use when flying to Plymouth from Grimsby. Booking flights from Humberside (HUY) to Plymouth should be relatively easy as there are 0 daily outbound flights to Plymouth from 2 different airlines.
This flight path from Grimsby Humberside to Plymouth was viewed by 30 users in the past month. Keep an eye out for changes in search interest prior to high and low season.