NOAA Ship Okeanos Explorer Begins 24/7 Sonar Mapping Run from Fiji Toward Honolulu

NOAA Ocean Exploration is leading a mapping expedition on NOAA Ship Okeanos Explorer from September 24 to October 19, 2026 — starting in Suva, Fiji and ending in Honolulu, Hawai'i. According to NOAA's expedition plan, the ship is running twenty-four-hour-a-day mapping operations using its full suite of sonars to map the seafloor, the water column, and the sub-seafloor.

The expedition focuses first on waters around American Samoa, before beginning the transit to Hawai'i while filling critical gaps in seafloor mapping data along the way. It follows the ship's recent ROV work in the region, including dives that documented polymetallic nodules on the abyssal plains of the Cook Islands' exclusive economic zone — the kind of baseline survey that informs both ecosystem protection and decisions about seabed minerals.

Why it matters: despite decades of satellite-derived depth estimates, only a fraction of the ocean floor has been directly mapped with sonar at modern resolution. High-quality bathymetry underpins tsunami and storm-surge modelling, cable and pipeline routing, habitat mapping, and any future resource decisions — and Pacific island nations in particular have had large, poorly surveyed areas within their own waters. Filling gaps in the central and south Pacific is a direct contribution to international efforts such as Seabed 2030.

This is a mapping-only expedition, not a diving one: no ROV dives are planned on this leg, so the discoveries will come as maps and water-column data rather than video. Sonar mapping has practical limits, too — resolution degrades with depth, operations depend on weather and sea state, and processing multibeam, backscatter and sub-bottom data into public products takes time after the ship returns. NOAA states the data will be made publicly available, which is what makes a transit survey useful long after the cruise ends.