We prepare disposable single-walled carbon nanotube network electrodes for the detection of the potent opioid fentanyl, currently a leading cause for opioid overdose deaths in the USA. We show repeatable dry transfer of single-walled carbon nanotube (SWCNT) networks to produce robust electrodes. This process directly produces highly conductive SWCNT electrodes without the need for any further modifications required for conventional carbon electrodes. The realized electrode showed low background currents combined with spontaneous enrichment of fentanyl, resulting in a high signal-to-noise ratio. With this electrode, a detection limit of 11 nM and a linear range of 0.01-1 μM were found for fentanyl. In addition, selectivity is demonstrated in the presence of several common interferents.