His travels began in the 1550's when he explored Africa's northwest coast. A navigator and an adventurer, Frobisher gained a reputation for preying on French trading vessels in the waters, off Guinea. He was arrested several times during the 1560's on piracy charges, but managed to avoid trial.
In 1576, Frobisher became commander of three small ships: the Pinnace, Michael and the Gabriel. He set sail for North America in search of the Northwest Passage. During his first trip he lost two ships and reached Baffin Island and discovered what later became Frobisher Bay. He sensed that North America was a land rich in gold and his tales of treasure earned him royal backing for his next two voyages in 1577 and 1578. He attempted to start at least one ill-fated settlement, but spent most of his time looking for precious metals. When he returned empty-handed after a third try, Frobisher lost his financial backing.
Frobisher returned to the seas in 1585 as vice admiral for Sir Francis Drake's voyage to the West Indies. Three years later, he fought for the English against the Spanish Armada and was knighted for his efforts. For six years Frobisher lead several different English squadrons, including one that attempted to intercept Spanish treasure ships in the Azores. He retired in 1591 and in 1592 Walter Raleigh persuaded him to lead an attack on Spanish merchant ships bringing gold from Panama. He was badly wounded at Siege of Crozon, near Brest, France. He was brought back to England but died in Plymouth on 22 November 1594.