On 3 November 1917, a royal resolution changed the spelling of the name of the municipality to Sandøy.

The official blazon is "Azure, three piles conjoined in dexter argent" (Norwegian: I blått tre sølv spissar som møtest i høgre skjoldrand).

This means the arms have a blue field (background) and the charge is a three triangles conjoined at a point along the left side.

The charge has a tincture of argent which means it is commonly colored white, but if it is made out of metal, then silver is used.

This was chosen since lighthouses play an important role in the safety in the municipality, which consists of 871 islands and skerries.

Sandøy consisted of 871 islands, but only five were regularly inhabited by the time the municipality was dissolved.

The main inhabited islands were Harøya, Sandøya, Finnøya, Ona, and Orta.

The municipal council (Kommunestyre) of Sandøy is made up of 19 representatives that are elected to four year terms.