The success of antiretroviral therapy (ART) requires continuous engagement in care and optimal levels of adherence to achieve sustained HIV viral suppression. We evaluated HIV-care cascade costs and outcomes of a community-based, mobile HIV-care, peer-delivered linkage case-management program (CommLink) implemented in Manzini region, Eswatini. Abstraction teams visited referral facilities during July 2019-April 2020 to locate, match, and abstract the clinical data of CommLink clients diagnosed between March 2016 and March 2018. An ingredients-based costing approach was used to assess economic costs associated with CommLink. The estimated total CommLink costs were $2 million. Personnel costs were the dominant component, followed by travel, commodities and supplies, and training. Costs per client tested positive were $499. Costs per client initiated on ART within 7, 30, and 90 days of diagnosis were $2114, $1634, and $1480, respectively. Costs per client initiated and retained on ART 6, 12, and 18 months after diagnosis were $2343, $2378, and $2462, respectively. CommLink outcomes and costs can help inform community-based HIV testing, linkage, and retention programs in other settings to strengthen effectiveness and improve efficiency.