[atlantic]

Not necessarily. The density of water peaks around 4ºC. So as oceans warm between 0º and 4º, they actually contract in volume.

[twawaaay]

Except water in oceans is at 4C (at least almost everything deeper than ca 200m). And in the vicinity of 4C the thermal expansion is very negligible. This graph should explain why: https://images.app.goo.gl/FXzvTkPvE9dYxoUA7

[atlantic]

Which supports the broader point that thermal expansion of water does not contribute to rising sea levels.