We present measurements of the timing accuracy and stability of Satellite Time and Location (STL) receivers with respect to UTC(NIST), the coordinated universal time scale (UTC) operated by the National Institute of Standards and Technology (NIST). Operated by Satelles, STL is a timing and location service that utilizes the Iridium constellation of 66 low Earth orbit (LEO) satellites. The service is available globally and resilient to regional outages of the Global Positioning System (GPS). We demonstrate that a typical STL receiver with an oven-controlled crystal oscillator (OCXO) can provide a stable output pulse with an average time offset near 10 ns and a maximum time offset of less than 200 ns with respect to UTC(NIST). We also present measurements of an STL receiver with a local rubidium oscillator that demonstrates improved short-term stability and a maximum time offset of less than 75 ns.