When the St. Lawrence II first started out she was affiliated with the Royal Canadian Sea Cadets Corps St. Lawrence, but eventually her program was opened to any participants ages 12–18 for a summer training cruises.

The ship sails mostly in the Great Lakes and the St. Lawrence River, but sometimes will venture as far as New York City.

The success of the St. Lawrence II was the inspiration for the construction and launch of her Toronto-based sisterships STV Pathfinder (in 1962) and TS Playfair (in 1973), with both training vessels also being designed by Francis A. MacLachlan.

Those who sign on to the St. Lawrence II for a course during the summer become trainees who comprise the basic unit of the ship and who complete most of the tasks, directed by petty officers.

The captain and the executive officer are usually the only people on the ship who are over 18 years of age, and they are the most qualified.