EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-167478) and in the Registration Statement on Form S-3 (No. 333-185246) of Mercer International Inc. of our report dated February 15, 2013 relating to the consolidated financial statements and the effectiveness of internal control over financial reporting, which appears in this Form 10-K.

/s/ PricewaterhouseCoopers LLP

Chartered Accountants

February 15, 2013

Vancouver, Canada