A low-cost hydrographic kayak surveying system was developed and is described here. The kayak survey system is an extremely flexible surveying system; it can be easily deployed in the nearshore, small lakes, and in other small bodies of water where engine-equipped vessels are prohibited. The cost and complexity of the system are minimized by using a low-cost L1 handheld global positioning system (GPS) system, a smart 200 kHz echosounder that outputs a serial depth string, and a simple off-the-shelf serial data acquisition system. The vertical and horizontal errors of the handheld GPS system are evaluated with an inexpensive external L1 patch antenna and a more expensive, nonpatch L1 antenna, resulting in vertical root-mean-square errors of 11 and 2.5 cm, respectively. In addition, bathymetric measurements at Bethany Beach, Delaware, were obtained using the kayak surveying system and compared to a wading and boat survey yielding a root-mean-square error of 17 cm. The kayak surveying system provides an easily constructed, environmentally friendly, low-cost surveying alternative to conventional and personal water craft surveying systems.