Illumina (ILMN) 8-K/A Grail Audited Consolidated Financial Statements As of and for the Years

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-3 (No. 333-254195) and Registration Statement on Form S-8 (No. 333-206215) of Illumina, Inc. of our report dated March 29, 2021 relating to the financial statements of GRAIL, Inc., which appears in this Current Report on Form 8-K/A.

/s/ PricewaterhouseCoopers LLP

San Jose, California

October 28, 2021