X0609 4 2026-10-01 0001750704 HawkEye 360, Inc. HAWK 0002127288 Serafini John Sheldon false C/O HAWKEYE 360, INC. 450 SPRINGPARK PLACE, SUITE 500 HERNDON VA 20170 true true false false President and CEO 1 Common Stock 2026-10-01 4 M 0 92329 0.23 A 647301 D Common Stock 2026-10-01 4 S 0 92329 14.7840 D 554972 D Common Stock 4545 I See footnote Stock Option (Right to Buy) 0.23 2026-10-01 4 M 0 92329 0.23 D 2027-02-08 Common Stock 92329 140943 D Represents shares exercised and sold pursuant to a Rule 10b5-1 Plan adopted on May 21, 2026. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $14.59 to $15.14 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold each separate price within the range set forth in this footnote. The shares are held by the Serafini Holding Trust Dated June 8, 2018, of which the Reporting Person is trustee and has voting and dispositive power. Fully vested. /s/ Michael S. Turner, Attorney-in-Fact 2026-10-02