Police said the items were taken from Beecraigs Fishery, in Beecraigs Country Park, West Lothian, between 5pm on Monday and 7am on Tuesday.
An attempt was also made to steal a motorboat from the reservoir but it was left abandoned in the water. Police said the canoes were worth £1000 each, with the trailer valued at £2000.
Sergeant Steven Stewart said: “We are appealing for anyone with any information regarding this incident to contact us.
“We would be very keen to hear, in particular, of anyone acting suspiciously in the park on Monday.”
Call Lothian and Borders Police on 0131-311 3131.