Can you get a lapras in soul silver?

yes, in the union cave every Friday. Make sure you save before attempting to catch a lapras. I would suggest catching a Scyther with false swipe and a paras with the move spore. (Scyther can be caught in the National Park on Tuesdays, Thursdays and Saturdays but it will take a while and you can catch a paras in llex forest, except in the afternoon which is between 10am-8pm) Sorry if you already knew this ;)