20 Oahu 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 59 Oahu beaches with a page here, 9 face the sunset in every month of the year and another 12 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 50° 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 22 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 7:18pm in Julyfaces north-westparking 65m from the sandtoilets 79mshowers
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces westparking 109m from the sandtoilets 14mshowers
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces north-westparking 98m from the sandtoilets 41m9 places to eat within 1km
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces south-westparking 43m from the sandshowersplayground
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces westparking 77m from the sandshowersdrinking water
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces north-westparking 34m from the sand5 places to eat within 1km130m long
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces westparking 197m from the sand1,090m long
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces westparking 102m from the sand270m long
sun sets over the water year-roundlatest sunset 7:18pm in Julyfaces north-westparking 546m from the sand51m long8 bus stops within 500m
sun sets over the water 10 months of the yearlatest sunset 7:18pm in Julyfaces north-westparking 31m from the sand1,273m long9 bus stops within 500m
sun sets over the water 10 months of the yearlatest sunset 7:04pm in Mayfaces south-westparking 81m from the sandlifeguard station mapped493m long
sun sets over the water 10 months of the yearlatest sunset 7:18pm in Julyfaces north-westparking 502m from the sandtoilets 84m605m long
sun sets over the water 9 months of the yearlatest sunset 7:18pm in Julyfaces north-west604m long8 bus stops within 500m
sun sets over the water 8 months of the yearlatest sunset 7:18pm in Julyfaces north-westparking 40m from the sandtoilets 7m12 places to eat within 1km
sun sets over the water 7 months of the yearlatest sunset 6:41pm in Marchfaces south-westparking 128m from the sand280m long
sun sets over the water 7 months of the yearlatest sunset 6:41pm in Marchfaces southparking 45m from the sand144m long
sun sets over the water 5 months of the yearlatest sunset 7:18pm in Julyfaces northparking 120m from the sand207m long2 bus stops within 500m
sun sets over the water 5 months of the yearlatest sunset 6:29pm in Februaryfaces south68m long7 bus stops within 500m
sun sets over the water 4 months of the yearlatest sunset 6:29pm in Februaryfaces southparking 503m from the sand107m long6 bus stops within 500m
sun sets over the water 3 months of the yearlatest sunset 7:18pm in Julyfaces north508m long
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.