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Planning a trip from Denver to San Francisco? KAYAK’s data-powered insights will help you find cheap flights. Learn the best time to fly, how early to book your ticket, and other tips to secure great prices.
The most affordable time to fly from Denver to San Francisco is generally on a Saturday in September.
Cheapest Route: The Denver to San Francisco route is the most cost-effective.
Booking Time: Book at least 90 days in advance to get the best prices.
Budget Airline: Frontier Airlines typically offers the cheapest flights for this route.
Flight Type: Direct flights are generally more expensive, consider flights with layovers to save money.
Flight Type: Direct flights are typically more expensive, consider flights with layovers for savings.
This feature is powered by ChatGPT: an OpenAI-developed artificial intelligence model trained with KAYAK proprietary data and third-party data not verified by KAYAK.
| Low season | September |
|---|---|
| High season | March |
| Cheapest flight | $76 |
Direct departures
Denver Intl to San Francisco
Monday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Tuesday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Wednesday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Thursday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Friday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Saturday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Sunday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Direct returns
San Francisco to Denver Intl
Monday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Tuesday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Wednesday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Thursday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Friday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Saturday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Sunday
Frontier, Southwest, United Airlines
Frontier, Southwest, +1 more
Delays delays delays. Late taking off, late landing, wait for a gate, etc.
Delays delays delays. Late taking off, late landing, wait for a gate, etc.
Connecting flight is on time and boarding was a breeze!
Very smooth checking in our luggage with a super pleasant SW agent. I enjoyed a fun entertaining movie.
WiFi did not work. For as outrageous as these flights cost, when they’re advertised with certain services/ features they should be in working order
First time traveling on Southwest since bag fees were implemented. Usual good service. Just more expensive now.
I would have liked to arrive on time - not 5 hours late!
It was a perfect flight in all aspects! Both legs!
Boarding process, crew were good. But the seats were so uncomfortable that was all I could focus on. I literally had to sit forward so that all 3 of us could fit in row. I will try to avoid Southwest in the future for any flights over 60 minutes.
1.5 hour delay, poor service, no compassion from the crew. Terrible experience
Great flight, 47 passengers on a 180 seat plane. Stewardess was pleasant and cheerful.
The internet service I paid for didn’t work at all and the flight crew was not very friendly.
Subject: Formal Complaint: Discriminatory and Unprofessional Conduct – Request for Immediate Action & Compensation Dear [Airline Customer Relations Team], I am writing to file a formal complaint regarding my recent travel experience with [Airline], which was by far the worst I have ever encountered. What occurred was not only unprofessional, but in several instances discriminatory, unsafe, and unacceptable. On the first leg of my trip, I arrived only four minutes past check-in. Instead of making any attempt to resolve the matter, your representative flatly denied me boarding and made me wait while she attended to passengers who arrived after me. By the time a manager intervened, it was too late to board, costing me time, money, and unnecessary frustration. The second leg of my trip (Chicago–San Francisco) raised even more serious concerns. From the outset, it was apparent that the staff—particularly two attendants—prioritized Caucasian passengers while dismissing African American and minority passengers. • When a Caucasian passenger in the exit row refused to comply with federal safety requirements, I, as a first responder, immediately offered to switch seats and assume the responsibility. My offer was blatantly ignored, and instead, a Caucasian passenger seated further up was chosen. This was discriminatory and deeply insulting, especially as I was actively de-escalating the situation that could have delayed the flight further. • During a lengthy tarmac delay of over 90 minutes, passengers were given conflicting and unreasonable instructions that created unnecessary distress and tension. • Throughout the flight, a visibly intoxicated passenger directly in front of me was disruptive, rude to others, failed to comply with seatbelt and electronic device rules, and yet faced no enforcement from the crew. In stark contrast, I was singled out for repeated compliance checks even though I was following every rule. This unequal treatment was so obvious that multiple passengers around me spoke up in my defense. This pattern of behavior demonstrated a clear lack of professionalism, disregard for passenger safety, and discriminatory treatment. I expect far better from an airline of your stature. As a paying customer subjected to this unacceptable treatment, I am formally requesting: 1. A full investigation into the conduct of the staff on both flights. 2. A written apology acknowledging the discriminatory and unprofessional behavior I endured. 3. Appropriate compensation for the distress, inconvenience, and mishandling of my travel. If this matter is not addressed promptly and thoroughly, I will have no choice but to escalate my complaint further, including filing with the U.S. Department of Transportation and sharing my experience through other channels. I trust [Airline] will take this complaint seriously and provide a timely resolution.
1. when we went to check in, our 2 first class seats had been CANCELED and the flight was sold out. This was done without our prior knowledge. It was all we could do to restore one first class seat for my wife and I flew economy. 2, Our flight home was scheduled to leave at 10:30 pm. Due to tsunami warnings, the roads were closed and our flight status was uncertain as to whether it would leave as scheduled. It was announced that it would now leave at 11:20 pm and the roads were now open since the tsunami had come and gone. We made a mad dash to the airport and checked in. Delays were announced at 12:30 pm, 1:30 am, 2:30 am and at 3:30 am it was canceled. Since this was a flight due to natural (tsunami) causes, there was no compensation. We were told to return at 1:00 pm the next day and our baggage would be kept on the plane since the same plane was going to leave at 1:00 pm. We had to return to our hotel for the rest of the night. The same plane did not leave at 1:00 pm and our baggage was gone! All in all, it was a miserable performance by UA. Information was hard to obtain and no one knew what was going on and what was going to happen. Hundreds of passengers slept on the floor, chairs, etc. No food and no water was made available to the passengers. It was a situation where UA could care less what was going on. As a one million mile flyer, I had not experienced anything like this before and it was hugely disappointing!
Boarded plane and then delayed 1.5 hours while on the plane
My flight was delayed a very short period of time but they did not hold my connecting flight to San Diego, also through United. So they closed the doors before we got off our plane. They would only have to help the door open for another five to ten minutes. So I missed a court deadline for a manditory mediation settlement conference for my client. I had to get an associate to be there in person and be on the phone with him relaying what he needs to do the entire time. The court was very upset with me and so was my client. United cannot be trusted.
Really good 😊 the woman at the gate entrance was a little rude checking in our carry-on but i dont think she worked for the airline, she worked for the airport at sacramento, other than that amazing.
Boarding was mayhem. Late boarding by 15 minutes because of lack of staff (missing 1 flight attendant. We had to wait for an arrival of another plane before we could board). Flight was a little rough, but cannot blame on airlines.
Great experience…left a bit behind schedule but made up fir that in the air and landed 10 minutes early 😁
United out of SFO is having issues with catering so none of our meals were loaded on the plane and no offer of compensation for our tickets purchased was offered.
A bit rush for transit. Food and entertainment are not available
Frontier is the Walmart of airlines. Frontier has removed adjustability and comfort from their seats to make the flight lighter and save gas. This makes it impossible to sleep on their flights. Their customer service is abysmal. Once, I bought a drink on the plane, and they swiped my credit card on the plane to pay for it. Then I got three weeks of daily notices from my bank telling me they tried to charge the wrong card number over and over again. I tried to call them, but they removed the ability to actually talk to someone that can resolve such a problem from their company to cut corners. The only way to talk to someone in person is to go to the check-in counter at the airport (40 minutes drive from my house). Eventually their system gave up on trying to charge the card, after 21 days of repeated tries. They don't pad their prices even a little to handle customer service issues like missed flights. They also have a blanket policy preventing helping you reschedule a missed flight if their system says you "cancelled" your own flight online. This is a major problem because their website is broken on mobile devices, the only web browser you have at the airport when their gate staff tell you that you have to reschedule your own missed flight online because they can't help you. I tried to reschedule my flight on my android device and instead, their website crashed and "cancelled" my missed flight. When I got to the counter, the agent argued with me for 5 minutes insisting that I intentionally cancelled my own flight (implying I had to buy another flight). She missed the point: the problem was that I could not buy another flight because their website is broken. I left to avoid more conflict with the "customer service" agent. I tried to redress my issue with their only other "customer service" chanel available: the contact form on their website. The response I got was more of the same: you cancelled your own flight, according to our website / computer records, therefore we won't help you. I was trying to explain the problem with their broken website that cost me hundreds of dollars by crashing / malfunctioning and resulting in a cancelled flight, but they only had deaf ears for this problem. Worst customer service I have ever experienced. I will never buy another Frontier flight again, because it is a risky, painful move that I will likely regret often.
What I expected, nickeled and dined and a frontier flight attendant loudly complained about her job and lack of communication as she headed to the gate on her cell phone. Not professional.
I’m not gonna fly Frontier Airlines because booking is not an option. No water or food is for high price, not equipped for health emergency incompetent crew for emergency services. Cheap airline shows it is cheaper in all service categories. Boarding is the best of all airlines!
Very bad! No good service delayed my second connection flight
Frontier is terrible. Paid for exit row, not given exit row, refused to refund fee.
2 hour delay due to late plane, wrong size plane causing overbooking, and people getting off and on the plane after boarding was completed.
The worst. We never made our connection and they did absolutely nothing to help us at the airport.
I never got to experience the flight because they delayed my first flight and I missed this one. Then Frontier didn't want to help me rebook a flight to get me to my final destination.
The Boarding process in Denver was chaotic, and since the line was so long, we were lined up very far from the gate. If there were any announcements from the gate staff, we didn't hear them. The flight attendants were spectacular. The only negative part of the flight was sitting by a 2 1/2 year old who was unruly and unfortunately had parents that matched his behaviors. Also, the restaurants in Denver on the E concourse, they didn't have food (passengers could only order 1 item on the entire menu) or the restaurants had 12-14 people waiting for orders to be prepared and another 6 people waiting to order. If you have a layover in Denver and need to grab food, be prepared to visit the shops with pre-packaged sandwiches, or you can visit another concourse but it may take a while to transit throughout the airport.
Everything went as planned. Crew was great. Seats were still not that comfortable.
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