From Croydon, hop on Southern or Thameslink from East Croydon station

https://gunnermaya718.trexgame.net/croydon-to-gatwick-airport-tram-train-and-bus-options

From Croydon, hop on Southern or Thameslink from East Croydon station. Trains to Gatwick are frequent and fast, often taking less than 20 minutes platform to platform.