Originally Posted by andymell

I've done connections onto the KE flight arriving as late as midnight without any issues. 9W may be able to interline for you. Are both flights on the same reservation (PNR)? If so, then interline will be more straightforward. If not, then you will need to show the KE reservation details at the counter. The one time I interlined to KE at BOM it was a little odd -- they had my luggage at their check-in counter. So, when I came to check-in, they found it and re-tagged it. This was nice is that I was confident that my luggage was not going to be lost on the transfer.

Regardless if whether you are interlining luggage or not, you'll need to go to the domestic baggage claim area to board the transfer bus. This will take you to the normal outside drop-off at the international terminal where you'll go through security, check-in, customs, security just lite a passenger originating in Mumbai. If you prefer, you could arrange a private car. They may still be traffic at 11 PM -- the bus avoids the traffic by driving inside the airport.

On arrival at the international terminal, you'll find plenty of porters ready and often able to assist you with your luggage and through the crowds to your check-in counter. Agree on a price before they take your luggage.

All-in, this will be a bit of an annoying connection due to the dom->intl transfer. And, if you can't interline your luggage you'll have to carry it a little ways (from the baggage claim to the bus). But, you've left plenty of time. Honestly, my biggest concern would be getting through security at the domestic terminal at midnight and having to spend three hours is that heckhole.