Yes, you can travel abroad using a valid passport from another country, subject to the law and rules of the country you are traveling to and in. Canadian law and rules do NOT govern.
Return to Canada by Road (arrival at PoE via land border crossing location, after border is "reopened"):
In regards to traveling back to Canada from abroad, posts above by
@Das67 mostly cover it. Bottom-line, contrary to what
@canuck78 asserts, if you are able to travel by road to a Canadian PoE (totally governed by U.S. law and rules up to the point you pass the U.S. border control station), you will be allowed entry into Canada . . . as a citizen of Canada . . . regardless what documents you present.
Technically you have the burden of establishing both your
identity AND Canadian
citizenship status at the PoE. Other than presenting a Canadian issued passport, practically this is best facilitated by presentation of a valid travel document (valid UK passport easily suffices) PLUS a form of identification denoting Canadian citizenship (such as those listed by
@Das67 above). That will make it easy.
If you present your UK passport plus some other form of identification corroborating your identity (ordinary drivers license plenty good enough, usually), it will likely go almost as easily so long as there is NO reason for PoE officials to be concerned about your actual identity. This may or may not involve a referral to Secondary to verify your identity and citizenship status, but even if there is a referral to Secondary, that should not be at all problematic (again, so long as there is NO reason for PoE officials to be concerned about your actual identity).
Even just presenting a valid UK passport will most likely suffice. There is a somewhat higher risk of a referral to Secondary for more thorough screening, to better verify your identity, but for most (for whom there is no reason to doubt their identity per the passport) the PoE officials will readily verify identity in GCMS. There is some risk border officials will be more or less cranky, even slow-walking the process, potentially issuing an admonition (as to carrying and presenting a Canadian passport or alternative, such as enhanced drivers license),
but ultimately once identity is established a Canadian citizen will be allowed entry into Canada.
In fact, a Canadian citizen has a Charter mandated right of entry into Canada.
Travel via U.S. Before Covid-19 Restrictions Are Lifted:
Even though your query is about travel AFTER the border is "reopened," it warrants noting that for Canadians (including PRs as well as citizens), the Covid-19 restrictions do not override what is described above, relative to being allowed to actually enter Canada. They do, however, impose collateral consequences which are applicable and enforceable for Canadians. These are of course TEMPORARY. They do not change the laws or rules governing immigration. They cannot be and are not being enforced in a way that will bar a Canadian citizen's entry into Canada, once the Canadian is at a Canadian PoE seeking physical entry into Canada. But entry can be subject to conditions . . . see, for example, media stories about Canadians offered a choice at the PoE, to return to the U.S. or to pay a fine (which can be quite steep), if they have not otherwise complied with the Covid-19 related restrictions.
All of which is of no relevance if, as your query indicates, the travel does not take place until AFTER the Covid-19 restrictions are lifted, after the border is, so to say, reopened.
Further Observations Regarding Canadians Abroad Returning to Canada:
I am not good at simplifying things (I tend to engage in more complex subjects, tending to wander into the
weeds), but I will try here.
The KEY to understanding the rules governing Canadians abroad returning to Canada is to clearly separate two things:
-- what is necessary to travel to Canada (the act of traveling to get to a Canadian PoE)
-- what is necessary to actually enter Canada (once the Canadian is at a Canadian PoE)
What is necessary to travel to Canada, in terms of documentation, depends on the mode of travel, whether the mode of transport is a commercial carrier (airlines typically) or is private. Canadian rules prescribing necessary documents to "travel" to Canada are about what documentation a Canadian must present in order to board commercial transportation coming to Canada. For Canadian citizens, for example, to board a flight headed to Canada from abroad, the Canadian needs to present either a valid Canadian passport or a special Travel Document (getting this is much easier, and faster, than the procedure for PRs obtaining a PR Travel Document).
That is totally separate and apart from the rules governing applications to physically enter Canada made at a PoE into Canada (mere arrival at the PoE constitutes making an application for entry).
Canadians (both PRs and citizens)
WILL BE ALLOWED ENTRY into Canada upon establishing identity and status, regardless what documentation they present to support this, and recognizing that for the vast majority, documentation sufficient to establish identity will suffice to also establish status (see previous discussion about this above for more detail).
FOR CLARIFICATION:
That is simply NOT correct.
No one can legally "
travel into Canada" from abroad without permission to enter Canada granted by proper border officials. Once this permission is granted, NO personal identification whatsoever is necessary to then "
travel into Canada." Canadian citizens are NOT required to carry identification while traveling in Canada.
What is necessary
to travel "TO" Canada depends, as I described above, on the mode of travel. For those traveling in a private vehicle on roadways leading to a PoE into Canada, there are NO Canadian rules which govern what documentation they need to carry. (I do not know what U.S. rules there are, if any, regarding what identification or other documents non-Americans must possess while traveling in the States.)
What a Canadian citizen needs to present to Canadian border officials, in terms of documents, attendant an application for entry into Canada, I outlined above. Bottom-line, so long as the traveler's identity can be established, a Canadian citizen WILL BE ALLOWED (given permission) to enter Canada, regardless what documents the Canadian presents to accomplish this.
