QuarterNorth Energy has a diverse portfolio of GOM deepwater subsea developments, several of which tie-into floating facilities owned and operated by others. QuarterNorth’s latest subsea development involves its existing Gunflint field, which ties into the Williams/Marubeni-owned Gulfstar 1 SPAR in Mississippi Canyon 724. The Gunflint development has been producing since 2016, and in May 2023 QuarterNorth added another well to this development. A tieback into a non-owned asset presents numerous commercial, technical, and operational challenges. These include multiparty negotiations to bring production to a platform with other operators’ oil and gas, upgrades to the platform's topsides systems, SIMOPS for drilling, subsea and facility execution, HSE, HAZOP/HAZID reviews and startup and commissioning to limit impact to ongoing production. Poorly executed, these efforts could result in significant delays which could drive up cost to the development as a whole. This presentation will explore these challenges and highlight lessons learned for future tiebacks to non-operated facilities.