Hello!

I don't know Denver at all, so hoping for some help with connection times.

My booking is Denver-Munich on Lufthansa at 4pm.
My plans changed and I need to fly first from Las Vegas to Denver on United (different booking code). Lands at 12:45pm - with a bag.

I need to get my bag, recheck it, back through security & get to the gate.

I have 3hours total time

Is this possible?

Lufthansa is a Star Alliance Partner with United so you should be able to have your luggage checked through to Munich when you check-in for your flight in Las Vegas - it shouldn't matter that your flights have different booking codes.

Regardless, 3 hours is more than enough time to make a connection in Denver.

More than enough. A lot of the terminal construction has been completed so it is easier to get around.

I would be comfortable with that, the problem comes only if your flight from Las Vegas takes off 90 minutes late, which is not likely but also not unheard of. If it happens, since United & Lufthansa are partners, you should be able to re-book your 2nd flight without penalty.........but that is probably going to be a flight on the following day.

Just be sure that Lufthansa is notified, don't be a "no show" for your 2nd flight if your first flight is late.

Three hours should be fine, especially since you should NOT* have to claim and recheck your bag in DEN. But knowing that things can always go sideways on day of travel... In your changed plans, did you purchase a separate ticket for LAS-DEN on UA or modify your original LH itinerary to add the UA flight?

If the former and there is some sort of delay in getting to DEN that makes you miss your flight to MUC your are on your own, though LH may show some mercy.
If the latter, you would be protected in case of such a delay and Lufthansa would put you on the next available flight without question.

*As noted, UA and LH are partners in Star Alliance which means you can check your bag at LAS all the way through to MUC. Just be sure that when you check in at LAS you have your LH itinerary available to show the agent so they can tag your bags through to MUC.

Thank you so much! I called LH & they were able to rebook to include the LAS flight. Your feedback is much appreciated!

Excellent - you should be in great shape now.