The young Edward joined the navy at the age of 12 aboard of 60 guns. "Superb" was sent to the West Indies with Admiral Francis Hosier. Boscawen stayed with "Superb" for three years during the Anglo-Spanish War. He was subsequently reassigned to , , and under Admiral Sir Charles Wager and was aboard "Namur" when she sailed into Cadiz and Livorno following the Treaty of Seville that ended hostilities between Britain and Spain. On 25 May 1732 Boscawen was promoted lieutenant and in the August of the same year rejoined his old ship the 44-gun fourth-rate "Hector" in the Mediterranean. He remained with her until 16 October 1735 when he was promoted to the 70-gun . On 12 March 1736 Boscawen was promoted by Admiral Sir John Norris to the temporary command of the 50-gun . His promotion was confirmed by the Board of Admiralty. In June 1738 Boscawen was given command of , a small sixth-rate of 20 guns. He was ordered to accompany Admiral Edward Vernon to the West Indies in preparation for the oncoming war with Spain.