James Cook became a seaman under Captain John Walker. in 1746.
James undertook several voyages from Whitby before leaving to join the Navy in 1755.
 

James Cook joined the Navy in June 1755 as an ordinary seaman, and joined His Majesty's Ship Eagle.
He then joined His Majesty's Ship Solebay as Master.
In 1758 he sailed in His Majesty's Ship Pembroke as Master from Europe to Newfoundland. 

During 1758 and 1759 James Cook was present at the important battles with the French at Louisbourg and Quebec in what is now Canada.
He then joined His Majesty's Ship Northumberland as Master, protecting the area from  the French. 
From 1762 to 1768 he was active in and around Newfoundland,.surveying the coasts during the summers, and producing charts back in London during the winters.