Can you leave Aus using Aus passport and arrive Singapore using another passport to check-in into Singapore?

Singaporeans do not understand that type of question since their country does not allow dual citizenship and they can only hold one passport. It is common use that Australians who hold dual citizenship like Australian/British depart Australia on the Australian passport and enter the United Kingdom on their British passport; hence do not need to undergo immigration procedures on arrival in both countries. Singapore immigration does not care on which foreign passport you are entering the country as long as it is valid for at least another six months on arrival and it is issued by the government of a country which does not need a visa for a visit. So if your Australian passport is almost going to expire and your Britsh or whatever other passport you legally hold is still valid another six months and entitles to travel without visa you may use that without problems. However since lots of countries are applying to the Advanced Passenger Information System (APIS) which demands airline companies to report the passport details of their passengers in advance you should book the ticket on the passport which you are going to use on arrival at the destination country. Singapore does not apply to the APIS hence it does not matter on which passport you have booked. Source(s): http://www.ica.gov.sg/page.aspx?pageid=96&secid=94 ..

Doesn't matter at all. You can leave Australia on your Australian passport (or whatever nationality you've chosen to be while in Australia) then when you arrive in Singapore use your EU/Japanese/Whatever second passport you have. Singapore customs don't care about your plane ticket. Everyone fills out an immigration entry card and on that card you can be whichever citizen you are. I did this in Egypt with a second passport several years old with NO stamps in it at all and they didn't care. I never knew of APIS, useful tip.

You can't do this, you must use the passport you departed on to enter another country, people try to do this to get through immigrations quicker. it isn't allowed.

Yes you can. As long as your Passport is valid for more than 6 months. My friend has 2 passports, Malaysia and Australia. She does it all the time.