OC Bus

Routes with numbers less than 100 are fixed routes that cover almost every city in Orange County. Buses operate on most major arterial streets. Route 1 is the only single-digit route, acquiring the number from California State Route 1. Routes 53, 57, and 64 also feature Xpress bus service with limited stop service between 6am and 6pm on weekdays. These buses are differentiated by adding an X to the end of each respective route.

Routes with numbers in the 100s descended from the old RunAbout service that formerly served residential neighborhoods, or provide service to portions of 1-99 routes that have reduced demand. Three routes (129, 143, 153) were truncated from routes 29, 43, 47, 53, and 59 as a result of March 2010 service change. These routes are operated by First Transit with the exception of routes 123 and 150 which were taken over by OCTA in February 2022.

Routes with numbers in the 200s are "OC Express," intra-county express routes which travel solely within Orange County and utilize the county's freeways. These routes run from park-and-rides and transit terminals to the business districts and back. These routes operate only during weekday rush hours.

Irvine Shuttle (iShuttle), operated by the OCTA at the Irvine Transportation Center in Irvine, California

Routes with numbers in the 400s are "StationLink" and Irvine Shuttle (iShuttle) routes which travel between Metrolink stations and business districts. These routes operate only during weekday rush hours and do not operate reverse peak services. These routes are operated by First Transit.

OC Bus on Bravo! Route 543 at Disneyland Resort in Anaheim, California

Routes with numbers in the 500s are "Bravo!" routes that operate on heavily used routes making limited stops and at transfer points to other routes. It is named according to the parent route it accompanies, for adding an B to the beginning of the route indicating express. Bravo! routes use a dedicated fleet of buses and have different color schemes from regular route buses.

Routes with numbers in the 700s are intercounty express bus services. Routes 701 and 721 go between Huntington Beach and Fullerton, respectively, and Downtown Los Angeles using the Harbor Transitway, while Route 794 connects Costa Mesa and Riverside. All three routes charge an additional fare in addition to the base fare. These routes operate only during weekday rush hours and route 721 is the only route that operates reverse peak services. Currently suspended due to COVID-19 pandemic.

Routes with numbers in the 800s are City Shuttle routes. Route 862, the first and only 800 series route, serving as a circulator route in Downtown Santa Ana and was introduced in October 2019, replacing former StationLink route 462.