Kayak and canoe owners are being urged to move their craft from beaches or slipways.
Tides are expected to reach a high of 10.2m tomorrow evening at 9pm, with a high of 10m expected tomorrow morning at 8.44 and 10.1m expected today at 8.18pm.
The notice from the Met Office warns that with an easterly wind of Force 5-6 expected tonight there is a risk of the sea over-topping the Victoria Marina.
A tide warning generally means that waves breaking of sea walls are expected to cause problems with water and debris affecting coast roads and walkways.
Wind speed is due to reduce to F3-4 by tomorrow evening's high water, but the warnings remain.
A statement from Agriculture, Countryside and Land Management Services said that owners of kayaks and canoes pulled up at the top of beaches or slipways should move them to their own property ahead of tonight's high tide to avoid them being washed away.
This followed the St Peter Port lifeboat and CI Airsearch being called out twice last month in Guernsey and Jersey to search for the occupants of empty kayaks found driving at sea.
'Owners are urged to clearly mark their craft either with an permanent marker or with one of Guernsey Coastguard’s “water-based activity” stickers available from local water-based sporting equipment suppliers so that emergency services can check if the occupant is safe,' said the statement.