Choosing a destination management company from abroad is inherently harder than choosing a local vendor — you can't easily visit the office or ask a colleague for a reference. That makes the vetting questions you ask upfront more important than they would be for a domestic booking.
Start with operational depth: does the company contract directly with hotels, transport, and production vendors, or subcontract through another agency? Direct contracting usually means faster proposal turnaround and clearer accountability if something goes wrong on the ground.
Ask for documentation, not just assurances: current liability insurance, business registration, and — for larger programs — references from groups of a comparable size. A DMC confident in its operations will have these ready.
Response time is a good proxy for how the company will behave during your actual program. If a detailed RFP takes two weeks to get a reply, that is useful information before you're relying on them for a 300-person conference.
Finally, ask how emergency situations are handled during a program — who is on call, what the escalation path looks like, and what happens if a flight is missed or a guest needs medical attention. A company that has a clear, specific answer has almost certainly needed it before.