Hi guys! So I'll be flying to Montego Bay, Jamaica in a few weeks and am very overwhelmed and confused with all of the connecting flights & immigration intricacies from stop to stop, so it would be fantastic if any of you here could help!

My flights to and from Montego Bay are as follows:
TO:
1 ticket:
KUALA LUMPUR -> LONDON -> MIAMI -> MONTEGO BAY

FROM:
1 ticket:
MONTEGO BAY -> CHICAGO -> LONDON
1 ticket:
LONDON -> KUALA LUMPUR

All flights are on American Airlines throughout and I have no checked baggage. I also plan to check in online beforehand and print my BPs before.

Questions:
1. In the KUALA LUMPUR -> LONDON -> MIAMI leg, will I need to go through immigration in London, or can I transit directly through a transit lounge?
2. Same question for the LONDON -> MIAMI -> MONTEGO BAY leg, will I need to go through immigration in Miami, or can I transit directly through a transit lounge seeing as it's all on 1 ticket?
3. Same question for the MONTEGO BAY -> CHICAGO -> LONDON leg.

Basically I'm a little unclear on when I need or don't need to pass through immigration in all of these different stops, as I understand border control may vary across countries.

In Miami you will have to deplane, clear Immigration, Customs and TSA Security before proceeding to gate to board your connecting flight. Same when returning through Chicago from outside the US.

If memory serves me correct in London there is a quick Passport Check, then you proceed to Security Checkpoint (or it may be Security first then Passport Control) and on to your connecting gate. If London Heathrow Airport, you may have to travel between terminals but procedures are the same as Shuttle Bus is inside the “secure area” - just follow signs for international connecting flights. Don’t recall if there is a need to change terminals if flying through London’s Gatwick Airport.

If your flights in London are through Heathrow Airport you can get step by step instructions for making the connections by entering your flight info here:
http://www.heathrow.com/flight-connections

If you are connecting through Gatwick go here for connection information: https://www.gatwickairport.com/at-th...t-connections/

Be sure to confirm which airline is actually flying each leg. AA does not fly Kuala Lampur to London, but BA does so I'm guessing the flight is a BA flight (even if an AA flight # / code share)

Unfortunately, since you cannot transfer airside in Miami, as you can in London, you will need a visa for the US unless you are a US citizen/permanent resident. Same problem with Chicago.

The requirement for a US visa depends on the OP's nationality which has not been disclosed. If they are eligible for visa waiver travel, they don't need a visa, they can apply online for an ESTA. If they are not from one of the visa waiver countries, they can apply for transit visas, one for MIA and the other for ORD.

Similar for the UK, a transit visa (direct airside transit visa) might or might not be required, depending on nationality. The fact that the transfer can be done airside at LHR does not automatically mean a transit visa is not required. It is all nationality based.

Interesting, Odin, I wasn't aware that some people needed transit visas for the UK. And certainly the OP's nationality is determinative. (Since you have to apply for ESTA, it is still something s/he needs to be aware of.) If the OP is Malaysian he does not need a visa for the UK but he does for the US.

https://www.gov.uk/transit-visa

https://travel.state.gov/content/vis...r/transit.html

It is a pity that he wasn't able to avoid routing through the US as the visa will be expensive and requires an interview.