"Until further notice, Yale libraries will admit only Yale students, faculty, and staff who have been approved for return to campus. A valid Yale ID with activated swipe access is required for entry. Special collections reading rooms will be open, by appointment only, with the same restrictions and requirements. The Classics Library is open only to graduate students and faculty in the Classics Department.
Yale College students who are enrolled remotely do not have access to library buildings and reading rooms. Students who have questions about the status of their campus access should check the Yale Hub [accessible only by Yale students]. Other patrons with questions about their campus access, including swipe-access to library buildings, should check with their home or sponsoring departments.
We regret that we cannot admit other Yale affiliates or non-Yale visitors at this time, due to restrictions on campus visitors, compliance with public health guidelines, and the University's prioritization of support for Yale teaching and research. "
-- From the Yale University Library's COVID-19 Update: Library Reopening FAQ, updated 6 October 2020.