Irvine is well-connected for a suburban city, with an airport practically on its doorstep and reasonable public transport options for Southern California.
By air: John Wayne Airport (SNA) is about five miles from central Irvine and handles a solid selection of domestic routes, including direct services to most major US hubs. It is significantly more convenient than LAX for anything in Orange County — shorter lines, faster baggage claim, and no battling through Los Angeles traffic on arrival.
By train: Metrolink's Orange County and Inland Empire–Orange County lines both stop at Irvine Station, connecting the city to Los Angeles Union Station and other Orange County destinations. Amtrak's Pacific Surfliner also calls at Irvine, making it accessible from San Diego and Los Angeles without a car. The station is in the southern part of the city; you will need a taxi or rideshare to reach most destinations.
By car: The two main freeways are the I-405 (San Diego Freeway) running northwest-southeast through the city, and the I-5 (Santa Ana Freeway) to the east. Both carry heavy commuter traffic during rush hours. Within Irvine itself, the city is designed for driving and distances between points of interest are typical of suburban Southern California — walkable only in small pockets, manageable by bicycle on the extensive trail network.