You can use any regex delimiter in your pattern substitution. No need to use / at all, try # instead. The following are equivalent:

:%s/find/replace/gc
:%s#find#replace#gc

Super useful for when you want to include / characters in your search and can avoid escaping them:

:%s/\/route\/path/\/new_route\/new_path/gc
:%s#/route/path#/new_route/new_path#gc