London to Colmar, France train advice needed

I am a foreigner also.
London to Paris Gare du Nord via E'star is the first leg.
The 2nd is Paris Gare de L'est to Strasbourg.
Change trains in Strasbourg to Colmar.
This is the better site:
https://www.trainline.eu/

read this about travel from London to Strasbourg (then to Colmar) via Paris or Lille

http://www.seat61.com/France.htm#London-to-Strasbourg-by-train

or you can get a train direct from Paris to Colmar

RailEurope is generally not the best place to buy tickets. I would book separate tickets for London-Paris at www.eurostar.com and trainline.eu for Paris-Colmar, but try trainline for the full journey and see if the fare is cheaper. The Eurostar arrives in Paris at Gare du Nord and you need to get to Gare de l'Est for the train to Colmar, but the two stations are in walking distance unless you have huge amounts of luggage. I would leave an hour between the trains just in case of delays on Eurostar, though.

You might additionally have to change in Strasbourg, but there are some through trains from Paris to Colmar. There are quite frequent trains from Colmar to Mulhouse or Basel, and many of them are TER services that don't offer advance purchase discounts.

Have you thought about flying? We are staying in Colmar 5 days. We plan to fly out of Mulhouse/Basel. I've been in contact with a taxi company, he said it was a 30 minute drive From Colmar. Our flight cost around $100 each. I checked into taking the train but it cost much more then flying.

Annabeth, All the above have given you correct info. London to Paris Gare du Nord (Eurostar), 10 minute walk and Gare de L'Est to Colmar (TGV), probably change at Strasbourg, but there are some through trains.
But, DO book both legs at the same time with the same company. That way, you are covered if the first train is late, you get a put on the next train at no extra charge. It is unlikely the Eurostar will be late, but best to be covered.

RailEurope is unlikely to have all the trains or the best prices, Eurostar won't sell you both legs, and SNCF is not the most user friendly site. I recommend https://www.trainline.eu/ or https://loco2.com/

Colmar-Mulhouse-Basel is easy and frequent, just buy at the station.

Thank you SO MUCH to everyone who replied!