Guam tourist visa is not required for citizens of Canada.
We strongly recommend traveling with 6 months validity on your passport at all times. Citizens of Canada can refer to www.canada.ca for forms and instructions for Canadian passport renewals.
Most destinations, including Guam, require that you have adequate unused pages in your passport, allowing for any necessary stamps upon arrival and departure. We recommend that you have at least two free pages in Visas section of your passport before any international travel. Canadian citizens cannot add extra passport pages to their passports. Please refer to www.canada.ca for forms and instructions for Canadian passport renewals.
Check with your airline in case you have connecting flights overseas as part of your journey to Guam. It may be the case that countries you pass through en route to your destination may require a separate transit visa. Please refer to visa requirements of the specific country.