c2c operates a train from Grays to Colchester every 20 minutes. Tickets cost $8 - $11 and the journey takes 24 min. 2 other operators also service this route. Alternatively, Arriva UK operates a bus from Grays to Colchester every 10 minutes. Tickets cost $6 - $9 and the journey takes 1 h 44 min. Arriva UK also services this route every 20 minutes.
From Grays train to West Ham Underground Station, Tube to Stratford (London), then train to Colchester. 1 h 25 min £28. From Grays, Bus Station (Grays Bus Stn) bus to Chelmsford City Centre, Railway Station (Chelm Rail Stn) then bus to Colchester Town Centre, High Street (Colch High St). 3 h 16 min £6. From Grays taxi to Colchester. 50 min £119. From Grays drive to Colchester. 50 min £9.