In 2008-9 the Centre for Early Scientific Learning (CRESL) at Bath Spa University worked with 10 primary schools in Bath and South Gloucestershire on the "Eco-monitoring at key stage 2" project, funded by the AstraZeneca Science Teaching Trust (AZSTT). As part of the project, the authors are writing a continuing professional development (CPD) unit for the AZSTT website to support teachers in running eco-monitoring activities. In this article the authors report on an eco-monitoring project using data-loggers and GPS technology. (Contains 4 figures and 4 online resources.)