24 Hour Urgent Care in Ontario, CA
Ontario CA is a major Inland Empire logistics hub adjacent to Ontario International Airport, served by Kaiser Permanente, Pomona Valley Hospital, and national chains with urgent care clinics along Holt Avenue, Euclid Avenue, and Milliken Avenue. The enormous Amazon, UPS, and FedEx warehouse workforce makes occupational health and industrial injury urgent care especially common.
Urgent care hours in Ontario, CA: The earliest opening time among Ontario, CA's 5 listed urgent care clinics is 8am, and the latest closing time is 11pm. 2 locations stay open past 9pm, and 5 are open on weekends — use the Open Now filter below to see who's currently accepting patients.
Filter clinics:
Urgent Care | Kaiser Permanente Ontario Medical Center
San Antonio Urgent Care Plus Ontario
Above Urgent Care Center
Prestige Medical Clinic and Urgent Care
Accelerated Urgent Care
What to Expect at Urgent Care in Ontario, CA
Listings are checked against Google's Places API and, where needed, the CMS NPPES provider registry — see how we verify listings. Hours change frequently, so please call ahead to confirm before visiting. Found an error? Let us know.
Health Considerations in California
California's climate varies dramatically by region: coastal areas experience mild temperatures year-round, while the Central Valley and Inland Empire face extreme summer heat, high ozone levels, and seasonal wildfire smoke that significantly worsens respiratory conditions. Wildfire season has expanded and intensified in recent years, making smoke-related respiratory visits — particularly for asthma, bronchitis, and eye irritation — common across northern and central California from summer through fall.
Urgent Care in Ontario, CA — Frequently Asked Questions
Is urgent care open on weekends in Ontario, CA?
Yes — 5 of the 5 urgent care centers listed above for Ontario, CA are open on Saturdays and Sundays. Some locations have reduced Sunday hours, so check the listings above for exact weekend hours at each clinic. If you need care on a Sunday evening, it's worth calling ahead to confirm the location hasn't closed early.
Do I need an appointment for urgent care in Ontario, CA?
No appointment is needed at most Ontario, CA urgent care centers. Walk-ins are welcome at all locations listed above. Some clinics offer online check-in so you can hold your spot in line before you arrive and reduce your time in the waiting room — check the clinic's website or Google listing to see if this is available.
How much does urgent care cost in Ontario, CA?
A typical urgent care visit in Ontario, CA costs between $100 and $200 without insurance for a basic exam. Additional services — such as X-rays, lab tests, rapid strep or flu tests, or stitches — will increase the total. Most clinics will provide a cost estimate when you call, and many post their self-pay rates on their website. See our full urgent care cost guide for a detailed breakdown.
Does urgent care in Ontario, CA accept Medicaid?
Many urgent care centers in Ontario, CA accept California Medicaid along with Medicare and major commercial insurance plans, but acceptance varies by clinic and by Medicaid managed-care plan. Call ahead to confirm the location takes your specific plan and is in-network before your visit.
What is the wait time at urgent care in Ontario, CA?
Wait times vary by clinic. Prestige Medical Clinic and Urgent Care is the highest-rated option among the 5 clinics listed here, at 4.9★. 2 of 5 stay open past 9pm for after-work visits. Weekday mornings tend to have the shortest waits industry-wide, and online check-in — where available — can reduce time in the waiting room.
What can urgent care treat in Ontario, CA?
Ontario, CA urgent care centers treat a wide range of non-life-threatening conditions including colds, flu, strep throat, ear infections, urinary tract infections, minor cuts and lacerations, sprains, rashes, pink eye, and more. Many locations also provide X-rays, lab work, and vaccinations. For chest pain, difficulty breathing, stroke symptoms, or other emergencies, go to the nearest ER or call 911.
Should I go to urgent care or the ER in Ontario, CA?
Choose urgent care for non-life-threatening conditions — infections, minor injuries, illness, and anything that isn't immediately dangerous. Go to the ER (or call 911) for chest pain, difficulty breathing, suspected stroke, severe bleeding, loss of consciousness, or any situation that could be life-threatening. Urgent care is typically faster and far less expensive for the conditions it's designed to handle. See our full ER vs. urgent care guide for more detail.
How many urgent care options does Ontario, CA have?
Ontario, CA has 5 listed urgent care clinics, averaging 3.9★ across 3,142 reviews. See the full list above for addresses, phone numbers, and hours.