Kīlauea on the Island of Hawai‘i is one of the most active and well-monitored volcanoes in the world. Its most devastating eruption of the last 200 years occurred in 2018, destroying more than 700 homes and other structures and displacing thousands of residents (Hawaiian Volcano Observatory Staff, 2018). As is common for Hawaiian eruptions, the lava flows from the 2018 lower East Rift Zone reached the coastline, where they produced prodigious plumes of toxic, corrosive steam and several spectacular hydrovolcanic explosions. As activity progressed, a significant volume of lava entered the ocean and was deposited on Kīlauea’s submarine slopes, where it formed a lava delta. Through funding provided by NOAA’s Office of Ocean Exploration and Research and the National Science Foundation’s Ocean Sciences Division, scientists aboard E/V Nautilus mapped the south flank of Kīlauea with the ship’s EM 302 multibeam echosounder to characterize this and other recently formed lava deltas.