Every Caribbean CBI brochure leads with the donation number: $200K (Dominica), $230K (Antigua), $235K (Grenada), $240K (St Lucia), $250K (St Kitts). That number is the smallest line in your actual budget.
Government processing fees. Most Caribbean programs charge $25-50K in processing and application fees for a family of four. Per-dependent uplifts apply: spouse, each child, each dependent parent. These fees are paid to the government and are independent of the donation.
Due-diligence. Independent international due-diligence firms investigate every adult applicant: financial background, source of funds, criminal record, prior visa refusals, political-exposure status. Costs run $5-15K per adult. For a family of four with two adults, that's typically $15-25K paid to the due-diligence firm directly.
Partner legal fees. Caribbean CBI runs through licensed local agents. Their fees are not included in the government processing fees and typically run $10-25K depending on family size and program complexity.
Document procurement. FBI background checks ($50-75 each, multiple needed at different points in the engagement), apostille services on every document submitted, certified translations where required, courier fees for delivering originals, biometric capture, medical certificates: $2-5K stack quickly.
The visit. Most Caribbean CBIs require one visit for biometric capture or the oath of allegiance. Round-trip airfare for a family of four plus a few nights of accommodation runs $5-15K depending on the country and travel timing.
The total. A $200K donation engagement (Dominica, smallest financial bar) typically runs $250-290K all-in for a family of four. A $250K donation engagement (St Kitts) typically runs $300-340K. The headline donation is roughly 70% of the actual cost.
The real-estate alternative. All five Caribbean CBIs offer a real-estate route at a higher principal ($300-400K) which is recoverable at exit (after a 5-7 year hold) rather than donated. For families who can deploy the larger principal and want recoverable capital, the real-estate route often nets out lower than the donation route over the full hold period.
Two pieces of advice from active engagements. First, model the all-in number at the start, not the donation number. Second, ask any agent who quotes you only the donation number to walk you through every other line item. If they can't, that's the signal you need.