dtl173

I am asking this question on behalf of my friend. He is a dual US/Canadian Citizen with NEXUS who lives in the Philly area. Next month, he is heading to Thailand with another friend of his for about three months. They will fly round trip together with KE YYZ-ICN-BKK. That trip includes a 2-night stopover in Seoul on the way to Bangkok and another 1-night stop on the way back to YYZ. That friend of his is based in YYZ, hence he chose it as the KE gateway so they can fly together.

My friend has already secured a Thai Multiple Entry Tourist Visa. The visa is on his US passport, not his Canadian one. He applied it from the Thai Embassy in DC for convenience purpose, rather than going to the much further one in Ottawa. When he enters his APIS into the KE website, should he be entering his US or Canadian passport? AFAIK, Canada does have APIS requirement and so does both Thailand and the ROK.

Scenario 1: He enters the CDN passport into his KE booking. The APIS sent to the Thai immigration will be the CDN one, not the US passport where his visa is located in one of the pages. Considering his length of stay in Thailand is beyond the 30-day visa exemption period, could KE @ ICN demand he show his Thai Visa when checking-in for the BKK flight? If that's the case and he shows the visa on the US passport, could the airline deny boarding since the APIS he provided reflects the Canadian passport? If check-in @ ICN concerning the visa proof turns out non-eventful, could he encounter problems with Thai authorities when he lands and hands to the immigration officer his US passport as it does not match with the APIS KE sent to them?

Scenario 2: He enters the US passport as the APIS into his KE reservation. On the way back when he checks-in for the return flight at ICN, the APIS KE sends to the CBSA reflects his US passport. When he arrives back in YYZ and scans his NEXUS card into the kiosk, could he land in hot water with the CBSA where they could deem this as a violation and revoke his NEXUS? As a CDN citizen, he is required to enter with his CDN passport.

Scenario 3: He enters the US passport as the APIS into his KE booking. During the middle or latter portion of his trip where he has already spent more than half or more of his time in Thailand, he calls KE reservation and ask them to change the APIS from the US to the Canadian passport. Is this possible?? Will airlines generally allow you to change passports on the APIS for tickets where several sectors have already been flown? In this case he would have already flown 50% of his ticket (2/4).