Exhibit 23.1
CONSENT OF INDEPENDENT AUDITOR
We consent to the incorporation by reference in Registration StatementsNo. 333-219333,333-198365 and333-167478, of Mercer International Inc. on FormS-8, and in Registration StatementNo. 333-213644, of Mercer International Inc. onForm S-3, of our report dated December 14, 2018 relating to the consolidated financial statements as of and for the years ended December 31, 2017 and 2016 of Daishowa-Marubeni International Ltd. (which report expresses an unmodified opinion and includes an amended consolidated financial statement paragraph stating that the consolidated financial statements for the year ended December 31, 2017 have been restated from those on which we originally reported on) appearing in this Current Report of Mercer International Inc. on Form8-K.
/s/ Deloitte LLP
Chartered Professional Accountants
Vancouver, Canada
December 14, 2018