The dynamics of single molecules are critical in determining how biological systems function. The number of measurement techniques to image and characterise single molecules is growing rapidly, however very few techniques are applicable in biologically relevant settings. Here, I provide a perspective on a relatively new field of research focused on the development of diamond-based quantum probes to measure the dynamics of single paramagnetic molecules in ambient aqueous solutions. The magnetic sensitivity of these quantum probes coupled with the biocompatible sensing platform offers a potential pathway towards 3D single molecule microscopy. (C) 2018 Elsevier Ltd. All rights reserved.