DECOSTOP Outdoor Centre is a dive shop in Lancaster, Ontario, Canada, serving divers from the nearby Montreal, Ottawa, Cornwall and Brockville areas at the gateway to the St. Lawrence River. The centre supports divers at every stage, from first-time certification through advanced and technical diving, offering scuba equipment sales with expert fitting, certification courses and continuing education, professional equipment servicing and maintenance, and rental gear selected for local and regional freshwater diving conditions. The shop also carries kayaks, stand-up paddleboards and paddle sport accessories for exploring the St. Lawrence River and surrounding waterways.