The Hornets – who made seven changes from last weekend’s win over Lewes – took the lead on 43 minutes through Chris Dickson.
Lucas Rodrigues cut the ball back for the evergreen striker to smash the ball past Gulls goalkeeper Bobby Mason.
And the visitors extended their lead on 53 minutes, courtesy of Rodrigues. The Brazilian met Reece Myles-Meekums’ cut-back to double Horsham’s advantage.
The draw for the FA Trophy second round will take place tomorrow [Monday, October 28].
This Saturday sees the Hornets travel to League Two outfit Chesterfield in the first round of the FA Cup.
You can catch all the build up online at sussexworld.co.uk/sport, and in print in this week’s West Sussex County Times.
See some of John Lines’ pictures from the game on this page and the ones linked, and read Horsham manager Dominic Di Paola’s thoughts in the West Sussex County Times, out every Thursday.
1. FA Trophy: Much-changed Horsham FC see off Canvey Island to reach second round - in pictures
Action from Canvey v Horsham Photo: John Lines
2. FA Trophy: Much-changed Horsham FC see off Canvey Island to reach second round - in pictures
Action from Canvey v Horsham Photo: John Lines
3. FA Trophy: Much-changed Horsham FC see off Canvey Island to reach second round - in pictures
Action from Canvey v Horsham Photo: John Lines
4. FA Trophy: Much-changed Horsham FC see off Canvey Island to reach second round - in pictures
Action from Canvey v Horsham Photo: John Lines