X0708 D/A LIVE 0002147310 Third Harbor Partners Fund I L.P. 3 HARBOR ROAD COLD SPRING HARBOR NY NEW YORK 11724 917-535-9360 DELAWARE None None Limited Partnership true 2026 NA Third Harbor Partners Fund I GP L.P. 3 Harbor Road Cold Spring Harbor NY NEW YORK 11724 Promoter General Partner of the Issuer. Dustin Gerard Smith 3 Harbor Road Cold Spring Harbor NY NEW YORK 11724 Executive Officer Mark Anthony Paolano 3 Harbor Road Cold Spring Harbor NY NEW YORK 11724 Executive Officer Pooled Investment Fund Private Equity Fund false Decline to Disclose 06b 3C 3C.7 true 0002147310-26-000001 true true true false 0 None None William Blair & Company, L.L.C 000001252 THE WILLIAM BLAIR BUILDING 150 NORTH RIVERSIDE CHICAGO IL ILLINOIS 60606-1594 All States false Indefinite 0 Indefinite false 0 9250000 true 0 true The sales commissions amount represents the aggregate sales commissions in respect of the issuer and its related investment vehicles in the offering. 0 true false Third Harbor Partners Fund I L.P. /s/ Thomas Walker Thomas Walker Chief Compliance Officer 2026-09-09