Travelling with two different passports [duplicate]

You are actually showing your passport to several different officials.

1. The airline.

   They will check your passport at check-in time to insure that you have the right to enter the country you are flying to. That is because under international treaties, if an airline delivers you to a country that you do not have permission to enter, they are legally obliged to fly you home on the next flight. This is costly and disruptive, so airline employees always carefully check your passport.

   Show the airline the passport that gives you the right to enter the country you are flying to.

2. Immigration officials at the country you are entering.

   If you hold a passport for the country you are entering, many countries' laws require you to show that passport. That is because they may want to track when their own citizens are coming and going.

   If you are entering a country for which you don't have a passport, show whichever passport gets you in easiest.

3. Immigration officials at the country you are leaving.

   Not every country checks passports on the way out (US doesn't), but when they do, always show the same passport that you used to enter the country. Otherwise their computer may decide that you've overstayed your welcome, or the official may be suspicious when s/he can't find the entry stamp in your passport. On the rare occasion that you need to get a new passport while overseas, keep the old expired one to show on exit!

4. Officials requiring proof of identity

   This may include anyone from money changers to airline officials to the TSA security checks in the USA. Show them whichever passport you want... they are just checking your identity and will trust any reasonable passport for that purpose.

One more guideline:

• In many situations, officials will have reason to suspect that you have another passport and ask to see it. This might happen, for example, if you are showing an airline official your passport for the destination country, but that passport does not confer the right to be in the country you're physically standing in. For example a dual Japanese/US citizen in Japan flying back to the US would show their US passport to check in to their flight back to America (according to principle 1), but the airline official might wonder why that passport doesn't contain a Japanese visa.

  In most reasonably free countries on good terms, you probably won't have to hide passports... dual nationality is a common feature and nobody at an international airport is going to be surprised or alarmed or decide that you must be a spy if you have two passports.

  That said, use common sense. A dual Israeli/US citizen travelling to Saudi Arabia on their US passport really ought to just leave their Israeli passport at home (or hide it well).

(I am assuming by China you mean the People's Republic of China.) In your case, the bigger problem than multiple passports is, according to Chinese nationality law (section 9), you automatically lose your Chinese citizenship when you voluntarily apply for and acquire another citizenship. So from a legal point of view, you are no longer a Chinese citizen, and your Chinese passport is not valid. Now, you may be able to hide this fact from the Chinese authorities, but that is kind of going into a slippery area.

If you want to keep pretending you are a Chinese citizen, then at the very least, I would definitely not let any Chinese official know about the Australian citizenship or passport. Otherwise, you should openly acknowledge to China that you have acquired Australian citizenship; which may mean you will have to return your Chinese passport to them (or let them invalidate it), and will almost certainly require you to get a visa to visit China.

You only need to show the one you're travelling with. I have two passports* as well, and NEVER use my South African one.

However, if you need to show the other one merely for ID for the plane ticket, then it's just like a form of photo ID, and only at the checkin counter. However, for the actual travelling bit, you'll know need to use one at a time.

(* It gets weirder, I actually travel with two NZ passports, one expired but with my valid UK visa in it, which I have to present each time I go there. But that's a different story)

If you have booked your ticket in your Chinese name I expect you are travelling from China, if this is true then you need to show both your passports to the airline and just the Chinese to passport officials.