There are 200 openings remaining in Sunday's OC Marathon, as well as spots available in the half-marathon and 5K races.
Online registration is available until Wednesday night at http://www.ocmarathon.com.
On-site registration will be available during the Active Lifestyle Expo, which runs Friday and Saturday at the OC Fair & Event Center in Costa Mesa.
The expo is free to attend, but there are parking fees, that also apply for race day. There is a charge of $8 for preferred parking or $5 for general parking. Preferred parking for race day can be purchased for $5 at the expo.