Electrical capacitance tomography (ECT) is a promising non-invasive imaging technique that is capable of mapping the dielectric permittivity of an object. ECT has great potential to be used as a new non-destructive evaluation (NDE) method. In the majority of NDE applications for ECT there is only limited access to the targeted objects, making conventional circular array ECT impractical. In this paper, a planar array ECT system is developed and proposed for 3D subsurface imaging as a form of limited access tomography. The sensor development, practical implications, capabilities and limitations of the proposed planar array ECT system are discussed. The experimental results are used to evaluate the system performance. A depth of up to 53% of the length of the sensor array can be achieved using experimental data using an array of 4 × 3 electrodes.