The Arun is one of the Sussex rivers that flows across a flat plain before entering the sea, and gives a long and fairly safe tidal stretch for paddling. The Arun was once part of the Wey and Arun Navigation, built to try and connect the Thames with the English Channel, and the former canal is currently being restored.
This part of the Arun is tidal – open access. H.W. at Arundel is Dover plus 1 hour 20 mins. At Amberley (halfway down), H.W. is Dover plus 2 hours, 40 mins. Pulborough H.W. tide times are Dover plus 3 hours 50 mins. The ebb tide can be very fast-flowing, the ebb lasting for 8 hours, the flood tide only 4 hours. The preferred option would be to start at Pulborough at, or just before, high tide, with the ebb taking the paddler down in two and a half to three hours, landing at Arundel before there is too much mud exposed.
There are no facilities or landing on the way down, except for Amberley, which is not very welcoming unless using the waterside restaurants, etc. Pulborough is a pleasant small town, and Arundel, with its castle, is a major tourist magnet, with all facilities. There is no (public) parking at Amberley, but both Pulborough and Arundel are well-provided for. Arundel Castle and cathedral are much visited. Brighton is only a short drive away to the east, and Chichester to the west.
Further useful information can be found on the following websites: