The British protectorate gained independence on June 26, 1960

Evidence

A delegation of key Northern leaders went to London to finalize the negotiations with the British government. … The negotiations were concluded, and the protectorate’s independence date was set for June 26, 1960. On the eve of independence, a trusteeship delegation led by assembly Speaker Osman went to Hargeisa to join in the festivities. — Abdi Ismail Samatar, Africa’s First Democrats, 462