20 Kauai beaches where the sun goes down over the water, worked out from each shoreline's orientation and the sun's position month by month.
Of the 34 Kauai beaches with a page here, 6 face the sunset in every month of the year and another 17 manage it for part of the year; the top 20 are ranked below. The seasonal ones exist because the point where the sun goes down swings about 51° along the horizon between the December and June solstices, which is enough to move it off the water at a beach that only just faces the right way. A further 3 beaches are left out entirely: their shoreline is too curved or too broken for us to state which way they look, and we would rather say nothing than guess.
This is geometry, not opinion. For each beach we know which way the shoreline looks, and we compute where on the horizon the sun sets in every month of the year. A beach makes this list when the setting sun falls inside its seaward arc — the sun actually goes down over the water rather than behind the land. Beaches that manage it in all twelve months rank first. One caveat we can't compute away: a headland, an offshore island or high ground can hide the last few degrees, and the maths doesn't see the skyline.
sun sets over the water year-roundlatest sunset 7:26pm in Julyfaces north-westparking 73m from the sandtoilets 78mshowers
sun sets over the water year-roundlatest sunset 7:25pm in Julyfaces south-westparking 69m from the sandtoilets 53m892m long
sun sets over the water year-roundlatest sunset 7:25pm in Julyfaces south-westparking 40m from the sandtoilets 54m3,943m long
sun sets over the water year-roundlatest sunset 7:25pm in Julyfaces south-westparking 407m from the sandtoilets 349m7 places to eat within 1km
sun sets over the water year-roundlatest sunset 7:25pm in Julyfaces north-westtoilets 65m314m long
sun sets over the water year-roundlatest sunset 7:26pm in Julyfaces north-westparking 534m from the sand2,263m long
sun sets over the water 9 months of the yearlatest sunset 7:09pm in Augustfaces south-westparking 27m from the sandtoilets 148mshowers
sun sets over the water 9 months of the yearlatest sunset 7:25pm in Julyfaces north-westparking 37m from the sandtoilets 49mshowers
sun sets over the water 9 months of the yearlatest sunset 7:25pm in Julyfaces north-westparking 66m from the sandtoilets 317m924m long
sun sets over the water 9 months of the yearlatest sunset 7:25pm in Julyfaces north-westtoilets 26m1,143m long
sun sets over the water 8 months of the yearlatest sunset 6:58pm in Aprilfaces south-westparking 82m from the sandtoilets 43mshowers
sun sets over the water 8 months of the yearlatest sunset 7:25pm in Julyfaces north-westparking 94m from the sandtoilets 54mshowers
sun sets over the water 8 months of the yearlatest sunset 6:58pm in Aprilfaces south-westparking 277m from the sand12 places to eat within 1km151m long
sun sets over the water 7 months of the yearlatest sunset 6:47pm in Marchfaces southparking 36m from the sandtoilets 40mshowers
sun sets over the water 7 months of the yearlatest sunset 7:25pm in Julyfaces northparking 84m from the sandpicnic tablesBBQ
sun sets over the water 6 months of the yearlatest sunset 7:24pm in Julyfaces northparking 301m from the sand1,805m long
sun sets over the water 6 months of the yearlatest sunset 7:25pm in Julyfaces northparking 301m from the sandBBQ91m long
sun sets over the water 4 months of the yearlatest sunset 7:25pm in Julyfaces northparking 66m from the sandtoilets 56m410m long
sun sets over the water 4 months of the yearlatest sunset 7:25pm in Julyfaces northparking 263m from the sandBBQ587m long
sun sets over the water 3 months of the yearlatest sunset 6:15pm in Januaryfaces southparking 58m from the sandtoilets 48m4 places to eat within 1km
Facilities, parking and shoreline data come from OpenStreetMap, and a beach can only be ranked on what somebody has mapped — "not mapped" is not the same as "not there". Distances are measured to the nearest point of the beach itself.