The route is currently operated twice-daily, but Eastern will add third rotations on Mondays, Thursdays and Fridays.
It means Eastern will now operate 17 flights a week linking the capital with the popular surfing destination on the north Cornwall coast.
Eastern said the rising cost of overseas holidays meant demand remained strong for UK breaks this summer.
The carrier added the new frequencies, which depart Gatwick at 1.55pm on Mondays, Thursday and Fridays would offer more choice for people looking to travel for leisure, business or to see family and friends.
