In November I am going from new Zealand, my flight is wellington to Auckland to San Francisco to Paris, first segment with air new Zealand and then other 2 with United airlines. I wanted to step out in San Francisco since it's much closer to Vancouver. My issue is that more than likely I'll have a checked in bag going under the plane. I have a 8h layover in San Francisco... Any one have suggestions on how to get my bag to skip the last segment?

I personally wouldn't take the chance on an 8 hour layover but I'd call the airline and see if your baggage is checked right through to the final destination or if you have to recheck I just got back from Costa Rica and my 7 hour layover in LA I had to recheck and go through security again.
Or I would of had to recheck but I did carry on only how long are you going for? Watch some youbtibs video on minimal packing I never thought I could do it but I just did 9 days with just a carry on and a small 12L daypack. You can get a locker at the airport for your carry on and go from there.

So you want to skip Paris altogether and go to Vancouver , a 20 hr drive from
San Francisco on an 8 hr layover?

I bought a crazy cheap flight (error fare) and I want to go home after several months travel back to Vancouver. So trying to figure out how to get my bag

Lol. Ok

I believe all checked bags must have a riding passenger. If the passenger misses or skips the flight, the checked bag is offloaded It is illegal to transport a bag without the passenger. I remember the flight crew mentioning this on the PA on a handful of flights that I've taken.

Mar I thot of that too but he would have to wait 8 hrs for them to load the bag, realize he’s not on the plane then off load it and collect it.

Actually! I think you will have to pick up your bag, go through customs and then re go through security (for the flight to paris) because it’s with different airlines AND
Because your landing as an international arrival and then your flight is booked as another international departure. So i think your in luck an actually have to pick up your bag right away!

I would call the Airlines and just ask the process when arriving in the us but I think all international arrivals have to pick up baggage and go through security because San Fran is your first spot of entry.
Also! If your interested check alliegent air for cheap flights from San Fran to Bellingham! I think that’s regularly on their schedule and is likely cheaper then renting a car to drive back (unless your wanting to road trip of course
)

Last flight I had through Peru on united airlines they were able to check my bag right through without having to pickup

When you land in the US from a foreign country you have to have all your baggage clear customs-it is a real pain-even if you stop coming from Mexico to Vancouver and stop in LAX.

Last flight I had through Peru on united airlines they were able to check my bag right through

That kind of thing seems to change from one trip to the next.

Did you book a RTW trip, or each segment separate?

No. I have a round trip flight from Paris to new Zealand and back... I just want to skip the very last segment to go back to Vancouver from San Francisco instead of doing it from Paris

Have your bag checked to SFO only, out of NZ.

Well sometimes they only check it right through... I'll see what united says

You have to pick up your checked bag then you can store it at airport. 8 hrs is not long to do much in sf cause the airport is far from things. Costly to store get taxi then see one place and back to airport. Why waste your money.

Isn't BART pretty quick into the city?

To a certain degree. Just saying that with only 8 hr layover, you need to get bag store it, be back at airport 2 - 3 hrs before you leave seeing how sf airport is nuts. That gives you a couple of hours in town.

bart goes every 20 min and stops along the way lets say you want to go to embarcadero prob be there in a short period of time. I generally do not take transit myself.. Yes I am a princss

We have taken BART, just couldn't remember how long it took to get downtown ... I hope the OP manages to make it work
maybe uber/lyft/taxi might be faster depending on traffic

So I finally phoned untied to confirm about my baggage. They would check it all the way through to Paris. But as long as I ask in new Zealand at checkin to grab my bags in SF or even in San Francisco I can request to get them to grab my bags... So not all cases they make you grab your bags because of customs