You can’t drink or carry open alcohol in a boat but you can transport sealed beverages - same as with vehicles. You can use cannabis only on boats used as temporary or permanent living space, and not when the boat is being operated.
Under the criminal code of Canada, drinking and boating carries penalties similar to drinking and driving a car. In addition, your motor vehicle driver’s licence can be suspended from 1 to 5 years. The mandatory minimum fine is $1000. Maximum prison sentence is 5 years. The laws are enforced by local, provincial and federal police - marine police carry alcohol-screening devices on the water.
You can be charged with Impaired Operation of a Vessel under the Criminal Code of Canada if your blood alcohol level exceeds .08 (80 milligrams of alcohol per 100 millilitres of blood), but you can be arrested even if it's lower. Nine of 13 provinces and territories impose administrative licence suspensions on drinking drivers at 0.05 or lower.
In all provinces of Canada, operating a boat while under the influence of alcohol is illegal. In some provinces, no one on board can consume alcoholic beverages while the boat is being operated. There are differences between provinces, but all require alcohol on board to be packaged and out of reach.
In Ontario, when you visit shore or even on your own boat, provincial law says you must not "display alcohol to the public". That might include a bottle of alcohol sitting in your boat's cockpit. Alcohol consumed at a picnic table on a dock or ashore is usually illegal.
Under Ontario Bill 209, drunk boaters will be subject to the same suspension penalties that now apply to vehicle drivers. The Highway Traffic Act applies to “anyone operating or having the care or control of a vessel”. Anyone found operating a boat while impaired can face an on-the-spot vehicle drivers licence suspension, with additional suspension if convicted.
Canadian border officials can deem people inadmissible at the border if they've been convicted of certain crimes, including drunk driving (car or boat). American laws are similar.
In most provinces, alcohol may be legally consumed on a boat with all of the following:
Check with the appropriate provincial authorities (OPP for Ontario, SQ for Quebec, RCMP for other provinces/territories) for current carriage restrictions.
In Ontario, it is illegal to carry alcohol in a car, snowmobile or boat unless the container is unopened and seal unbroken, or unless the beverage alcohol is packaged in baggage that is fastened closed or not otherwise readily available to anyone in the vehicle. In a boat, the beverage alcohol must be stored in a closed compartment. (Alcohol and Gaming Commission of Ontario)
Cannabis is now legal everywhere in Canada, but provinces will have separate regulations for sale and usage. In general, you will not be able to consume it (smoking, vaping, eating) in a vehicle or boat that is being driven. Also boats must be used as a temporary or permanent living space to carry or use Cannabis.