What is the opposite of unmissable?

The opposite of "unmissable" depends on what aspect of the word you're focusing on:

If you're focusing on the idea of something being highly noticeable or attention-grabbing:

* Unremarkable

* Ordinary

* Bland

* Overlooked

* Inconspicuous

* Forgettable

If you're focusing on the idea of something being essential or not to be missed:

* Optional

* Dispensable

* Skippable

* Irrelevant

If you're focusing on the idea of something being impossible to miss:

* Missable (this is the direct opposite, but it's not a commonly used word)

The best opposite will depend on the context of the word "unmissable."