Ahi, Mahi, and Marlin Season Building Offshore Across the Hawaiian Islands

What's Biting

What's Next

With trade winds holding steady at 8–9 m/s across the buoy network, offshore conditions are unlikely to shift dramatically over the next 48–72 hours absent a significant weather system. The most actionable near-term variable is swell attenuation on leeward coasts — anglers targeting west-facing waters may find slightly improved sea states by midweek as the current northeast swell wraps around each island's volcanic shield.

The waning crescent moon is approaching new moon territory around May 19–20. This lunar transition is meaningful for Hawaiian offshore fishing: darkening nights concentrate baitfish deeper and push ahi aggregations toward fish aggregating devices (FADs) and offshore ledge drops during daylight hours. Early-morning departures timed to reach grounds at first light — typically between 5:30 and 7 a.m. in mid-May — tend to outperform midday sessions during this phase. Weekend anglers planning runs for May 16–17 should target those early-morning windows before trade winds build through the afternoon.

Water temperatures of 74–79°F fall squarely in the preferred range for the Islands' primary offshore targets. Mahimahi respond well to floating debris lines and surface temperature breaks at these readings — anglers who can run 20–40 miles offshore and work rip lines where color changes mark productive blue water stand the best chance of intercepting mahi schools. Wahoo (ono) are a strong secondary target on the same trolling spread; high-speed runs of 15–18 knots with wire leaders are standard when targeting this species.

Blue marlin historically build through May on the Kona grounds as surface temps climb toward and past 78°F — with buoy 51002 already logging 79°F on south-facing waters, the thermal fingerprint that precedes the summer marlin push is forming. Skirted lures and rigged natural baits trolled 20–50 miles offshore are the proven approach as the season transitions toward peak months.

Current swell heights of 5.9–7.9 feet are workable aboard larger offshore-capable vessels, but trailered or smaller center-console boats should monitor the NOAA marine forecast and wait for a sub-4-foot window before committing to a blue-water run. Leeward harbors on the western shores of each island offer the most reliable departure conditions given the northeast swell orientation.

Context

Mid-May in the Hawaiian Islands typically marks a transition from the quieter spring offshore period into the buildup toward peak summer pelagic production. Surface water temperatures in the mid-to-upper 70s°F recorded across this week's buoy network are consistent with — and on south-facing stations slightly above — seasonal norms for this time of year, an encouraging early sign heading into the core summer season.

No direct comparative signals from the current intelligence feeds address how this May is tracking against prior years in Hawaii specifically. Hawaii Fishing News functions as the state's official catch record-keeper and publishes moon and tide resources that anglers rely on throughout the season, but no week-over-week trend data was available in this reporting cycle. HI Sea Grant's recent publications addressed marine policy fellowships and coastal resilience programming rather than in-season fishery summaries. When direct comparative data is absent, we note it rather than speculate.

What general seasonal history tells us: May is one of the more accessible offshore months in Hawaiian waters. It falls ahead of summer crowd peaks, before the sustained south swells of June through August that can limit blue-water access on south-facing coasts, and during a period when northeast trade winds typically remain consistent rather than switching to the variable Kona winds of winter. Charter fleets on the Kona grounds have historically begun targeting blue marlin more aggressively once surface temperatures cross the 77–78°F threshold — a mark the south-facing buoy network has already reached this week, suggesting the seasonal clock is running on schedule or slightly ahead.

Inshore, giant trevally (ulua) and various reef species typically strengthen through late spring as water temps rise — a pattern consistent with general Hawaiian angling knowledge at these surface readings, though no current-week source confirmed or contradicted that pattern for this specific reporting period.