At sea, you're hours from the nearest hospital and outside the reach of your regular health coverage. That's the entire argument for travel insurance on a cruise — everything else is detail. Here's the detail, kept short.
Medical coverage is the part that matters. Most domestic health plans cover little or nothing outside the country, and a ship's medical center bills like a private clinic. A policy with real medical and emergency evacuation coverage is the difference between an incident and a catastrophe. Read the medical limit first; the trip-cancellation part second.
Cancellation coverage protects the deposit, not just the fare. Cruise deposits are real money, and cancellation penalties escalate as the sailing approaches. "Cancel for any reason" upgrades exist — they cost more and reimburse a portion, not all. Worth it for complex, expensive journeys; often unnecessary for a simple short sailing. There's no universal answer, only your trip's math.
Timing matters. Many policies' best benefits — including pre-existing condition waivers — are only available if you buy within a couple of weeks of your first trip deposit. This is the single most common insurance mistake in cruising: deciding to "think about it" and thinking past the window.
The honest summary: insure the medical risk always; insure the cancellation risk in proportion to what you'd lose; buy early enough to keep your options. We don't sell insurance ourselves — we make sure you understand it before you sail, and point you to the right questions for your policy.