HMS Beagle was a Cherokee-class 10-gun brig-sloop of the Royal Navy, one of more than 100 ships of this class. The vessel, constructed at a cost of £7,803 (roughly equivalent to £638,000 in 2018), was launched on 11 May 1820 from the Woolwich Dockyard on the River Thames. Later reports say the ship took part in celebrations of the coronation of King George IV of the United Kingdom, passing through the old London Bridge, and was the first rigged man-of-war afloat upriver of the bridge. There was no immediate need for Beagle so she "lay in ordinary", moored afloat but without masts or rigging. She was then adapted as a survey barque and took part in three survey expeditions.

The second voyage of HMS Beagle is notable for carrying the recently graduated naturalist Charles Darwin around the world. While the survey work was carried out, Darwin travelled and researched geology, natural history and ethnology onshore. He gained fame by publishing his diary journal, best known as The Voyage of the Beagle, and his findings played a pivotal role in the formation of his scientific theories on evolution and natural selection.