Oh a beach walk is beautiful! So relaxing. I know alot of people who run after giving birth. But I guess it is a case by case basis. If you want to run, may be worth double checking with your doctor. There are alot of fitness gurus who specialise in post partum exercises to build the strength back up.
Jasmin Paris - one of the worlds most phenomenal ultra runner. Raced and won a 260 mile race whilst also stopping to breast feed about 6 - 10 months after giving birth. Mind BLOWN!