Should I choose a teacher recommendation for the University of Hawaii application if it's optional?

For the University of Hawaii, an optional teacher recommendation is usually not necessary for most applicants, especially if your grades, course rigor, and application already give a clear picture of your academic ability. If the rest of your application is solid and there is nothing important that needs added context, skipping the recommendation is usually fine.

A recommendation can still help in specific situations. It is worth submitting if a teacher can add something your transcript does not show, such as strong intellectual curiosity, major improvement over time, meaningful class leadership, or readiness for a particular program. It can also be useful if there is a weak spot or unusual circumstance in your record that a teacher can credibly explain.

What matters most is quality, not just having an extra document. A detailed letter from a teacher who knows your work well is much better than a generic one saying you were responsible and nice. If the recommendation would just repeat what is already obvious from your grades and activities, it probably will not change much.

So for most students, optional really does mean optional here. Submit one only if it adds clear new value to your application, not just because the box is available.