Yes, travel insurance is close to essential for a trip to Tabiteuea South, one of the more remote atolls in Kiribati's Gilbert Islands chain, and the honest reason is evacuation logistics rather than any dramatic danger on the atoll itself. Local medical services here are minimal, and the real question a policy needs to answer is not whether something might go wrong but how far you would need to travel to get it treated at all.
Serious cases on Tabiteuea South are typically stabilized locally if at all possible and then flown to South Tarawa, Kiribati's capital atoll and the country's main hospital hub, itself a domestic flight away. From there, anything beyond what Tarawa's facilities can manage generally means a further transfer abroad, commonly toward Fiji, since Kiribati's own referral arrangements lean that way for complex cases; confirm your policy explicitly covers this kind of multi-leg medical evacuation rather than only a single transfer.
Remoteness itself is the core risk profile here - domestic flights within Kiribati run on limited schedules, and a missed connection or weather delay can extend a simple trip by days rather than hours. Trip-delay cover is worth checking closely given how thin the transport network is between outer atolls like Tabiteuea South and the capital. There is no meaningful seasonal storm pattern beyond general Pacific cyclone exposure further from the equator, so the honest emphasis stays on distance and infrastructure rather than weather.
Keep any clinic paperwork from Tabiteuea South or Tarawa, airline documentation for delayed domestic flights, and receipts for any emergency transport, since records are easy to lose track of this far from services. Many policies require notice before major expenses like evacuation are incurred, so check the claims process in your policy wording well before you travel, and check whether your existing health cover extends abroad and specifically to Kiribati before relying on it.