What can I do to make sure I have access to my Canadian phone number even though I am currently living in Britain or Italy?

I live in three different countries in one year, Canada, Italy and Britain, and I am having trouble with accessing two factor authentication when I log in to my banks, (in Canada). What can I do to make sure i have access to my Canadian phone number even though I am currently living in Britain or Italy?

[Re-Titled by Moderator]