International customary laws are generally considered to be automatically part of Canadian law so long as they do not conflict with existing Canadian legislation (R v Hape  2 SCR 292, ) - this is a monist approach to the implementation of international law. In contrast, Canada follows a dualist approach with respect to the domestic effect of international treaties. This is similar in approach to other Commonwealth countries such as the United Kingdom, Australia and New Zealand. While ratification of a treaty creates international obligations for Canada, the dualist system means that in order for the treaty obligations to be given the force of law domestically, Canada cannot simply become a party to the treaty - the treaty must be incorporated into domestic legislation.
Sources: Elisabeth Eid, Interaction between international and domestic human rights law: a Canadian perspective, and Azeezah Kanji, Applying International Law in Canadian Courts: A Pocket Guide for the Perplexed.
Canadian international treaties are all available in full text online on open access databases.
The Canadian Government Global Affairs Canada Treaty Law Division website includes:
Most Canadian treaties are also deposited with the United Nations and become part of the United Nations Treaty Series (UNTS), or its predecessor, the League of Nations Treaty Series (1920-1944). Searching by 'Participant' will find all Canadian treaties, provide the UNTS citation, and link to the full text of the treaty, including in force and signature information etc.
For more information about treaties, see the Treaties page on our Public International Law Research Guide.
If a treaty is included in a treaty series, the treaty series should be cited rather than eg: the UN document number. Treaties are often included in several treaty series. According to Chapter 7.4 (pp 125-127) of the Australian Guide to Legal Citation, treaties should be cited in the following preferential order:
2. An official treaty series of a state party. For Canada, this is the Canada Treaty Series.
3. Another international or regional treaty series.
4. International Legal Materials (ILM) (University of Melb staff & students only). This series is on HEIN Online (vol 1, 1962+) in the Law Journal Library collection and in JSTOR (vol 1, 1962+) . This is not a treaty series - but it includes treaty texts and useful introductory information about the treaties, and it is an accepted method of citation. Note that JSTOR's holdings are more up to date than HEIN.
5. If the treaty is not included in any of the above, use the official document number (such as a UN document number) to identify it, using the accepted style as described in Chapter 8 of ACLC3.