SEOUL—South Korea, enjoying a slowdown in new coronavirus infections, is contemplating life after social distancing.

Calling them “social-prevention measures,” Seoul officials are preparing new guidelines to kick-start the lengthy return to normalcy as early as next month. Students might be allowed to return to school with zigzag seating arrangements in classrooms and temperature checks, restaurants might have to install screens to separate diners before reopening, and workers could be allowed to shuffle to offices.

A...