Circular connectors normally have either separately installable crimp contacts, or factory installed solder contacts. (The latter may be available as hermetically sealed assemblies.)
Perusing the Lemo catalog, I note that they seem to offer "crimp contacts with reduced solder cups" which is strange and contradictory (see page 130).
I'll also note that designing with circular connectors involves many special accessories and tools and may not be worth it just for hobby use.