Minecraft wiki entry for Ocean, associated text: A deep ocean, with an ocean monument in the background.
View of an old pre-Java Edition 1.13 frozen ocean.
Another view of a frozen ocean.
A reef less area of a warm ocean, with some sea pickles.
Another view of a deep lukewarm ocean.
An example of the random temperature variation within frozen oceans. The darker areas are colder, and have snowfall and ice sheets; the lighter areas are warmer, have rainfall and unfrozen water.
Same as the previous image, edited for better visibility.
An example of an ocean before Aquatic Update.
Sea pickles generating in an underground ravine.
A wrecked ship in an iceberg at a frozen ocean.
A small lukewarm ocean, looking like a bigger lake.
A school of 6 cod swimming in an ocean.
A ravine, shipwreck, ruin, and dolphins beneath the surface of an ocean.
Looking down into a deep ocean.