The earth was formless and void, and darkness was over the surface of the deep, and the Spirit of God was moving over the surface of the waters. -Genesis 1:2
Are we to assume these waters did not constitute one or more oceans?
“Waters” can mean a number of things. The topic is debatable as to just what conditions are being described Biblically, let alone beliefs outside of that, from science or elsewhere.
However, if there were large bodies of surface water, there would be evaporation. Evaporation would mean clouds, clouds would mean rain. There was no rain, plant life was watered via mists that arose from the ground.
There were also no rainbows. That was a covenant from God, to never again destroy the world by flood.
Taken together, this means that there were no oceans. Others disagree.