If you're a citizen of a visa-exempt country, you can apply for a work permit directly when you arrive at a Canadian port of entry rather than applying in advance. However, if your job requires a Labour Market Impact Assessment that hasn't been completed, you generally must apply before arrival.
(2)A foreign national may not apply for a work permit when entering Canada if (a)a determination under section 203 is required, unless(i)the Department of Employment and Social Development has provided an assessment under paragraph 203(2)(a) in respect of an offer of employment — other than seasonal agricultural employment — to the foreign national, or(ii)the foreign national is a national or permanent resident of the United States or is a resident of Greenland or St. Pierre and Miquelon; (b)the foreign national does not hold a medical certificate that they are required to hold under subsection 30(3); or (c)the foreign national is a participant in an international youth exchange program, unless they are a national or permanent resident of the United States or their application for a work permit was approved before their entry into Canada.