Gatwick has official luggage storage in both terminals before security, operated by Excess Baggage Company. Use it if you are returning to LGW.
Airport storage is the simplest choice for a Gatwick connection or a later flight. If you are taking the train into London or Brighton, city storage can work better when it avoids returning to the airport just to collect bags.
London Gatwick lists Excess Baggage Company luggage-storage facilities before security in both the North and South terminals. Gatwick also states that there are no lockers for luggage storage due to security reasons.
Compare Gatwick luggage storage
Choose based on whether you are staying airport-side, going into London, or travelling south toward Brighton.
Official airport service
Gatwick Excess Baggage Company
Best for storing luggage at Gatwick before a later flight, terminal change or short airport-side wait.
North Terminal before security, Level 1 next to Costa Coffee
South Terminal before security, Level 2 behind check-in zone E