Hello,
To tech in Canada, you need a TESL Canada certificate. If you already have a CELTA, you can contact TESL Canada to get the equivalency.
To get TESL Canada certification, you need to take a course that's recognized by TESL Canada, such as Ontesol's 250-hour online course with practicum, and obtain the equivalency from your BA form the UK at a company called WES or another called CES. You can visit www.tesl.ca and www.ontesol.com for more information.