Final answer:
Captain James Cook is the explorer associated with both observing the icebergs from Antarctica and discovering Hawaii during his third major voyage.
Step-by-step explanation:
The voyage associated with the observation of icebergs from Antarctica and the discovery of Hawaii is that of Captain James Cook. Cook undertook three major voyages across the Pacific Ocean, and it was during his third voyage that he encountered the Hawaiian Islands, which he initially named the Sandwich Islands.
Ferdinand Magellan is known for commissioning the first voyage to circumnavigate the globe, but he did not observe icebergs from Antarctica nor did he discover Hawaii. Christopher Columbus discovered the New World but was not associated with Antarctica or Hawaii, while Vasco da Gama's voyages were primarily around the Cape of Good Hope to India.