From the M5:

Leave the motorway at J11a and follow the A417 into the A419. Follow the A419 for approximately 20 miles - leave it at B4696, 'Spine Road Junction', Signposted Cotswold Waterpark. Follow the Spine Road for a short distance passing The Four Pillars Hotel on your left. Take the next right signposted Windrush and Isis Lakes.

From the M4:

Leave the motorway at J15 head north following the A419 in the direction of Cirencester, following the brown tourist signs for The Cotswold Water Park. Follow the A419 for about 15 miles, and leave it at B4696, 'Spine Road Junction', Signposted Cotswold Waterpark. Follow the Spine Road a short distance passing the hotel on your left. Take the next right signposted "Windrush and Isis Lakes".