http://icbc.bc.ca/Licensing/lic_renew_replace_new.asp
If you are new to B.C. and drive a vehicle, you need to obtain a B.C. driver’s licence within 90 days after moving here.
It is best to apply for your B.C. driver’s licence well within 90 days of moving to British Columbia. New residents who hold a Canadian, American, Austrian, German, Swiss, Japanese or South Korean licence can usually complete their licence exchange the same day, provided they bring:
Primary and secondary identification
Their current licence, and
Proof of driving experience
(Acceptable translations of these documents may be required.)
あまり文章がクリアじゃないんですが、もしカナダで車を運転しているならば、3ヶ月以内にBCの免許に変えるのが必要(つまり、日本の免許だけで3ヶ月は運転できる)だとしか書いてなくて、3ヶ月以内に免許を変えないと駄目だとは書いてないと思う。
翻訳が必要かはそのオフィスによって違うようですね。