Which fish is the largest alive, and which sea has no shore at all? This ocean trivia runs in five rounds of 12. Tap a choice, then Check answer to read why.
Read the full guide
Five rounds, from the surface to the trench
The five oceans and Sea creatures hold most of the easy questions; The deep sea and Salt, currents and waves hold the hard ones. Pick a round under Topic, read the four choices aloud, and press Check answer once every team has written a letter. Keep the score on paper.
Ocean trivia questions to print, with the key
Choose a Topic, then Print question sheet for the questions with lettered choices, and Print answer key for the answers with the reason for each.
Tips
Play The deep sea last: its answers of about 4 km and about 11 km start the best arguments.
Questions and answers
What are some easy ocean trivia questions?
Which is the warmest of the five oceans? Which is the smallest and the shallowest? What does a blue whale eat almost nothing but? The answers are the Indian Ocean, the Arctic Ocean and krill.
How were the answers checked?
Each was read on September 23, 2026 in the English Wikipedia article linked under it, and figures are as those pages gave them: the Challenger Deep at 10,935 metres, the Draupner wave at 25.6 metres.
Why is the largest animal not a question?
Other quizzes on this site already ask it, along with the narwhal's tusk and the meaning of tsunami. This set asks what they skip: the largest fish, the largest brain and the largest eyes in the sea.
About how much of Earth's surface does the ocean cover?Answer: About 71%. Source: Wikipedia: Ocean
About how much of the world's ocean water sits in the Pacific?Answer: About half. Source: Wikipedia: Pacific Ocean
The Atlantic takes its name from which figure of Greek myth?Answer: Atlas. Source: Wikipedia: Atlantic Ocean
In 1513 Vasco Núñez de Balboa sighted the Pacific from Panama. What did he call it?Answer: The Southern Sea. Source: Wikipedia: Pacific Ocean
The Pacific covers about how much of Earth's surface?Answer: One-third. Source: Wikipedia: Pacific Ocean
The Pacific Ocean is bigger than what?Answer: All of Earth's land put together. Source: Wikipedia: Pacific Ocean
The Southern Ocean is larger than only one other ocean. Which?Answer: The Arctic Ocean. Source: Wikipedia: Southern Ocean
The Southern Ocean is usually taken to be the water south of which latitude?Answer: 60° south. Source: Wikipedia: Southern Ocean
Which body settled the debate over the Southern Ocean's limits in 2000?Answer: The International Hydrographic Organization. Source: Wikipedia: Southern Ocean
Which current flows all the way around Antarctica?Answer: The Antarctic Circumpolar Current. Source: Wikipedia: Southern Ocean
Which is the warmest of the five oceans?Answer: The Indian Ocean. Source: Wikipedia: Indian Ocean
Which ocean is both the smallest and the shallowest of the five?Answer: The Arctic Ocean. Source: Wikipedia: Arctic Ocean
Show all 60 questions (48 more)
The deep sea 12
About how deep is the Challenger Deep, the lowest known point of the Mariana Trench?Answer: About 11 km. Source: Wikipedia: Mariana Trench
About how deep is the ocean on average?Answer: About 4 km. Source: Wikipedia: Ocean
Around deep-sea vents, bacteria feed tube worms and clams without sunlight. What process do they use?Answer: Chemosynthesis. Source: Wikipedia: Hydrothermal vent
Black smokers, chimney-like vents on the sea floor, were first found in 1979 on which undersea ridge?Answer: The East Pacific Rise. Source: Wikipedia: Hydrothermal vent
The Challenger Deep is named after survey ships of which navy?Answer: Britain's Royal Navy. Source: Wikipedia: Challenger Deep
Down to about what depth does enough sunlight reach in the open ocean to form the photic zone?Answer: About 200 metres. Source: Wikipedia: Ocean
The first vehicle to reach the bottom of the Challenger Deep, in January 1960, was a bathyscaphe. What was it called?Answer: Trieste. Source: Wikipedia: Challenger Deep
In 2004 a Japanese research team took the first pictures of which animal alive in its deep-sea home?Answer: The giant squid. Source: Wikipedia: Giant squid
In March 2012, which Canadian film director dived alone to the bottom of the Challenger Deep?Answer: James Cameron. Source: Wikipedia: Challenger Deep
The Mariana Islands, which gave the trench its name, were named for whom?Answer: A queen of Spain. Source: Wikipedia: Mariana Trench
What shape is the Mariana Trench?Answer: A crescent. Source: Wikipedia: Mariana Trench
Where does the glowing lure of a deep-sea anglerfish get its light?Answer: From bacteria living in it. Source: Wikipedia: Anglerfish
Sea creatures 12
How many species of sea turtle are alive today?Answer: Seven. Source: Wikipedia: Sea turtle
In a clownfish group, what happens when the breeding female disappears?Answer: The breeding male becomes female. Source: Wikipedia: Clownfish
In the Middle Ages, narwhal tusks were sold as the horns of which creature?Answer: The unicorn. Source: Wikipedia: Narwhal
The orca, or killer whale, is the largest member of which family?Answer: The oceanic dolphins. Source: Wikipedia: Orca
Sea cucumbers belong to which group of sea animals?Answer: Echinoderms. Source: Wikipedia: Sea cucumber
What do box jellyfish have that other jellyfish lack?Answer: True eyes with lenses. Source: Wikipedia: Box jellyfish
What does a blue whale eat almost nothing but?Answer: Krill. Source: Wikipedia: Blue whale
What is the largest fish alive today?Answer: The whale shark. Source: Wikipedia: Whale shark
Which animal has the largest brain on Earth?Answer: The sperm whale. Source: Wikipedia: Sperm whale
Which animal has the largest eyes of any living creature, except perhaps its colossal cousin?Answer: The giant squid. Source: Wikipedia: Giant squid
Which is the largest of all living turtles?Answer: The leatherback. Source: Wikipedia: Leatherback sea turtle
Which whales are known for long, complex songs sung by the males?Answer: Humpback whales. Source: Wikipedia: Humpback whale
Salt, currents and waves 12
About how salty is seawater on average?Answer: About 3.5% salt. Source: Wikipedia: Seawater
As the Gulf Stream heads toward Europe, what is it called?Answer: The North Atlantic Current. Source: Wikipedia: Gulf Stream
At typical salinity, at about what temperature does seawater freeze?Answer: About −2 °C (28 °F). Source: Wikipedia: Seawater
European discovery of the Gulf Stream dates to the 1512 voyage of which explorer?Answer: Juan Ponce de León. Source: Wikipedia: Gulf Stream
On January 1, 1995 the first rogue wave ever measured digitally hit a platform in which sea?Answer: The North Sea. Source: Wikipedia: Rogue wave
The Sargasso Sea is named after what?Answer: A floating brown seaweed. Source: Wikipedia: Sargasso Sea
The Sargasso Sea is the only named sea without what?Answer: A land border. Source: Wikipedia: Sargasso Sea
The warm water the Gulf Stream carries makes which region milder than others at its latitude?Answer: Northwest Europe. Source: Wikipedia: Gulf Stream
Where does the Gulf Stream begin?Answer: In the Gulf of Mexico. Source: Wikipedia: Gulf Stream
Which two ions make up most of the salt in seawater?Answer: Sodium and chloride. Source: Wikipedia: Seawater
Why do scientists avoid calling a tsunami a tidal wave?Answer: Tsunamis have nothing to do with tides. Source: Wikipedia: Tsunami
The word thermohaline, for ocean circulation, joins temperature with what?Answer: Salt content. Source: Wikipedia: Thermohaline circulation
Reefs, explorers and records 12
About how many new species of sea life did the Challenger expedition find?Answer: About 4,700. Source: Wikipedia: Challenger expedition
About how many separate reefs make up the Great Barrier Reef?Answer: About 2,900. Source: Wikipedia: Great Barrier Reef
The Aqua-Lung was invented in 1942 and 1943 by engineer Émile Gagnan and which French naval officer?Answer: Jacques Cousteau. Source: Wikipedia: Aqua-Lung
The Aqua-Lung was the first self-contained underwater breathing gear to succeed worldwide. What is such gear called?Answer: Scuba. Source: Wikipedia: Aqua-Lung
The Great Barrier Reef is the world's biggest single structure made by what?Answer: Living things. Source: Wikipedia: Great Barrier Reef
The HMS Challenger voyage of 1872 to 1876 laid the foundation of which science?Answer: Oceanography. Source: Wikipedia: Challenger expedition
In which sea does the Great Barrier Reef lie?Answer: The Coral Sea. Source: Wikipedia: Great Barrier Reef
In which year was the Great Barrier Reef chosen as a World Heritage Site?Answer: 1981. Source: Wikipedia: Great Barrier Reef
Nemo, in the name Point Nemo, is Latin for what?Answer: Nobody. Source: Wikipedia: Pole of inaccessibility
The ocean around Point Nemo is known as a cemetery for what?Answer: Spacecraft. Source: Wikipedia: Pole of inaccessibility
Point Nemo in the South Pacific is the place in the ocean farthest from what?Answer: Land. Source: Wikipedia: Pole of inaccessibility
World Oceans Day takes place every year on which date?Answer: June 8. Source: Wikipedia: World Oceans Day
How this list was compiled: Written for this site; nothing was copied from another list. Questions and wrong choices are our own. Each explanation restates facts from the page named and linked beside it, in our own sentences; numbers and dates follow that page. Each answer was checked on 2026-09-23 against the page named and linked beside the question: the text of that English Wikipedia article (https://en.wikipedia.org) was fetched that day, and the passage that states the fact was read before the question was kept. Depths, areas and lengths are the figures those pages gave on that day, rounded as the question says. Left out on purpose: sea-level, temperature and species counts that change year to year, anything about fishing catches or pollution totals, and facts other trivia sets on this site already ask (the largest ocean, the largest animal, the narwhal tusk as a tooth, the meaning of tsunami, the octopus's hearts, the Bay of Fundy tides, the country beside the Great Barrier Reef, the cause of tides, and the 1960 dive's pilot). Levels are our estimate: easy is fair for any table, medium suits people who like the sea, hard will stump most tables. Each question also carries the date its page was read (checkedOn). Licence: own work