Explanatory Note

This Post-Effective Amendment No. 98 under the Securities Act of 1933, as amended (the “Securities Act”) (Amendment No. 98 under the Investment Company Act of 1940, as amended (the “1940 Act”)) to the registration statement on Form N-1A (the “Registration Statement”) of Vanguard Wellesley Income Fund (the “Trust”) is being filed pursuant to paragraph (b)(1)(iii) of Rule 485 under the Securities Act solely for the purpose of delaying, until November 13, 2025, the pending effective date of the Trust’s 95th Post- Effective Amendment. By way of further background:

Post-Effective Amendment No. 95 was filed under Rule 485(a)(2) on August 18, 2025, to register shares of Vanguard Wellington U.S. Value Active ETF, a new series of the Trust. Post-Effective Amendment No. 95 originally requested that the Amendment become effective on November 3, 2025.

This Post-Effective Amendment No. 98 incorporates by reference the information contained in Parts A, B, and C of Post-Effective Amendment 95 to the Registrant’s Registration Statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant hereby certifies that it meets all requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the Town of Valley Forge and the Commonwealth of Pennsylvania, on the 16th day of October, 2025.

VANGUARD WELLESLEY INCOME FUND

BY: /s/ Salim Ramji*

Salim Ramji

Chief Executive Officer, President, and Trustee

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated:

*By: /s/ John E. Schadl

John E. Schadl, pursuant to a Power of Attorney filed on February 28, 2025 (see File Number 33-64845), Incorporated by Reference.