Ponce de Leon park in Punta Gorda. 
Not really a beach per se because it is difficult to go into the water, but has sand, view and a great sunset.  Bring you chairs.

Port Charlotte Beach Park
4500 Harbor Blvd.
Port Charlotte, FL 33952
Fishing, bocce ball, picnic shelter, playground, restrooms and a recreation center.
Englewood Beach
2100 N. Beach Rd.
Englewood, FL 34223
Pavilion, boardwalk, grills, picnic shelters, playground and more.
Englewood Beach in Charlotte County about 45 minutes from Punta Gorda.

Stump Pass Beach State Park
900 Gulf Blvd.
Englewood, FL 34223
Located at the southernmost end of Manasota Key.

Don Pedro Island State Park
Between Knight and Little Gasparilla Islands
Boca Grande, FL 33921
Swimming, shelling, picnicking, hiking and fishing.

Siesta Key Public Beach
A little drive from Punta Gorda but one of the finest sand beaches in the entire world.  Winner of numerous awards and acclamations.  Lifeguards are on duty all year long.  A great beach experience! 

Punta Gorda on the
Punta Gorda to Siesta Key Public Beach
About one hour and 55 miles.
I-75 N toward TAMPA.  41.3 mi   
Take the SR-72 W exit, EXIT 205, toward SIESTA KEY/SARASOTA.  0.4 mi     
Turn LEFT onto CLARK RD/FL-72 W. Continue to follow FL-72 W.  5.8 mi     
Turn SLIGHT RIGHT onto MIDNIGHT PASS RD/FL-758.  1.3 mi  
MIDNIGHT PASS RD/FL-758 becomes BEACH RD/FL-789A.  0.7 mi   
Turn RIGHT onto CALLE DEL INVIERNO.  0.1 mi   
Turn RIGHT onto CALLE DEL OTONO.  0.2 mi     
Turn RIGHT onto AVENIDA DEL MARE.  0.1 mi     
Turn LEFT onto BEACH RD/FL-789A.  0.2 mi  
900 BEACH RD is on the RIGHT.       

All information deemed reliable but not guaranteed.