Through check in, airport change?

Hello,
I am having a flight arriving Kansai airport in the early morning (8-ish), with a domestic flight on the same ticket heading on to Sapporo from Itami airport.

I think the bag will be checked through all the way to Sapporo (have to get it through customs though) but not sure if I get checked in all the way, meaning saving some time in Itami airport perhaps?

Does anyone know how it works?

The bag will not be checked through to CTS. You have to physically carry it on the bus or train to ITM and re-check it there for your flight to CTS.

International flights switching to a domestic flight you have to pick up your bag and clear customs - that is standard everywhere I've traveled. Even if it is the same airport.

Yeah, I understand that I need to bring it through customs. But can I be checked in all the way, just dropping off my bag at the departure airport (HND)?

In case it would save some time and hassle...

Yeah, I understand that I need to bring it through customs. But can I be checked in all the way, just dropping off my bag at the departure airport (HND)?

If you mean you have a connecting flight from HND to KIX and then ITM to CTS..... (I hope not because thats weird way to connect)

The answer is no. It must follow the same airlines and route that you take.

You will need to pick up bag at KIX, ride train or bus to ITM and recheck in the bag.

Hope thats helps!

Haha, you are right, it should not be HND. I am too tired to write. Sorry for the confusion.

Would not it be better to fly directly from HND to CTS or HND to NRT and CTS ( Jetstar could be cheaper) , instead of HND to KIX and then to ITM and CTS. What a waste of time and money?

You might want to consider flying directly to CTS from KIX with Peach Air:
http://www.flypeach.com/pc/en

The OP said it's on the same ticket so I wouldn't call that a waste of money as I remember the domestic ticket is not much more than buying only international flight.

But buying a new ticket would certainly be a waste of money, don't you think?

It all boils down to this: if you are switching airports, no matter if it's a domestic to domestic flight or an international to domestic flight, you are responsible for your luggage and must take it to the other airport to check it in. The airlines don't provide courier service from airport to airport for luggage.

Just to add to what @John B says. At least at Haneda if you are transiting from international to domestic it is your responsibility to get your luggage between the terminals. However if you are going from domestic to international then your luggage is taken care of for you.