Hawaii-based Airlines - Question re: when to pay HA checked bag fee

My son is flying NWA from SFO to HNL and then flying HA from HNL to LIH.

A couple of questions:
1) Can he check his bags through to LIH?
2) Does he pay the HA checked bag fee when he checks in online?
3) Is it the same process in reverse when he comes back?

Thanks for your help!

A couple of questions:
1) Can he check his bags through to LIH?
Yes. Tell the NW/DL agent at check-in to "interline" his bags through to LIH. Then doublecheck the tag to make sure that it reads LIH rather than HNL. More here: http://www.flyertalk.com/forum/hawaii/761311-guide-connecting-thru-honolulu-intl-airport-other-hawai-i-airports-05-03-09-a.html
2) Does he pay the HA checked bag fee when he checks in online?
No. It's the "accepting" carrier (i.e., the carrier that accepts the bags) whose fees you must pay. If non-exempt from the fee, your son will have to pay the NW bag fees. Note that you still have to check-in with an agent to interline your bags through to LIH.
3) Is it the same process in reverse when he comes back?
Yes. Interline the bags through to the final destination and pay the bag fees of the accepting carrier, which in this case is HA. So HA's fees should apply (which should be first bag free, second bag $17 since this is an interisland flight).

Yes. Interline the bags through to the final destination and pay the bag fees of the accepting carrier, which in this case is HA. So HA's fees should apply (which should be first bag free, second bag $17 since this is an interisland flight).

Now I'm confused, Slippahs. Recently I posted about a similar situation. I flew NW SEA-HNL-ITO r/t. Booked on NW, all flight numbers were NW. SEA-HNL on NW metal, HNL-ITO on HA metal. When I checked in at ITO for my return, HA told me $20 each for two bags I was going to check. (I left the bags there with my daughter).

Interestingly, my daughter is flying the same itinerary in reverse, all on HA, in a couple weeks. She was quoted $15 first checked bag, $25 second checked bag.

I never looked at their website because I assumed that because my tickets were booked on NW, NW flight numbers, that my NW status would exempt me from the checked bag fee. Note: I didn't check bags going over.

And I'm curious...what would happen if I flew the same flights but checked bags here in SEA? Because all segments were booked on NW, I didn't have to request an interline. Would NW have collected the fees on behalf of HA or would HA have charged them when I checked in in HNL?

Now I'm confused, Slippahs. Recently I posted about a similar situation. I flew NW SEA-HNL-ITO r/t. Booked on NW, all flight numbers were NW. SEA-HNL on NW metal, HNL-ITO on HA metal. When I checked in at ITO for my return, HA told me $20 each for two bags I was going to check. (I left the bags there with my daughter).
I'm confused too. Where did they get $20 from? $20 is neither HA nor NW's cost for a first or a second bag fee. It should've been $17 unless there's some hidden interline fee that I don't know about (and non-disclosure of such a fee on HA's website would be a big :td: ).
Interestingly, my daughter is flying the same itinerary in reverse, all on HA, in a couple weeks. She was quoted $15 first checked bag, $25 second checked bag.
That's the correct charges. $15 for 1st, $25 for second when flying HA to the Mainland. (free for 1st, $17 for second when flying HA between two Hawaiian islands)
I never looked at their website because I assumed that because my tickets were booked on NW, NW flight numbers, that my NW status would exempt me from the checked bag fee. Note: I didn't check bags going over.
No, it's the first operating carrier's rules that apply to checked bags. Since the first segment you had departing ITO was on HA, HA's rules should apply (but again, no clue on the $20 charge).
And I'm curious...what would happen if I flew the same flights but checked bags here in SEA? Because all segments were booked on NW, I didn't have to request an interline. Would NW have collected the fees on behalf of HA or would HA have charged them when I checked in in HNL?
NW-HA don't have the ability to transfer baggage fees between each other. If you didn't interline, you'd be exempt from the bag fees when flying NW per your elite status but would most likely be charged it when checking your bags in HNL.

OK, mahalo, Slippahs. :)

I don't know where the $20 per bag figure came from either, but the two agents repeated it multiple times - $20 per bag, $40 total. And if I understand it correctly, they should only have been charging an interisland fee anyway, because I was on NW metal from HNL to SEA.

I was caught unaware because I clearly hadn't been in this situation before and I was looking at it solely from the ticketing carrier's angle.

(Good thing I wasn't trying to check my mochi!)

And if I understand it correctly, they should only have been charging an interisland fee anyway, because I was on NW metal from HNL to SEA.
Actually, to the best of my knowledge, they shouldn't have charged you anything since each pax is entitled to one free checked bag on interisland flights. Again, perhaps there's something different when you're interlining to a Mainland flight? It'd be the first I've ever heard of it though.

Does it matter that he purchased two separate tickets-- SFO-HNL-SFO on NWA and HNL-LIH-HNL on HA?

We've done this before and not had a problem with the interline check-in, but the whole checked bag fee still confuses me.

If I understand slippahs correctly, he'll pay the NWA fees on the way to Hawaii and HA's fees when he returns to the mainland. Is that right?

Thanks again for helping me get this straight.

If I understand slippahs correctly, he'll pay the NWA fees on the way to Hawaii and HA's fees when he returns to the mainland. Is that right?
Yes, the carrier that accepts the bags (at check-in) gets to decide the rules.