Last February, I was sitting in a coffee shop in North Park, scrolling through flight prices to Seattle and nearly choking on my cold brew. $340 for a roundtrip? For a flight I’d taken dozens of times for half that price? That’s when I realized I’d accidentally been searching for flights during Presidents’ Day weekend – basically one of the worst times to fly this route.

I backed out, adjusted my dates by just four days, and boom – $87 roundtrip. Same airlines, same airports, wildly different price. That moment reminded me why I’m kind of obsessed with tracking this particular route. I’ve probably flown San Diego to Seattle about 20 times over the past few years (I’ve got family up there, plus Seattle’s coffee scene keeps calling me back), and I’ve gotten pretty good at knowing when to book and when to wait.

The thing is, this route can be incredibly affordable or surprisingly expensive depending on how you approach it. Let me walk you through what’s actually worked for me, including the mistakes I’ve made so you don’t have to repeat them.

Why This Route Is Perfect for Budget Travelers (Most of the Time)

The San Diego to Seattle corridor is pretty competitive, which works in your favor. You’ve got Alaska Airlines treating it like a hometown route since Seattle is their hub, Southwest running frequent service, and Delta jumping in occasionally. When airlines compete, prices tend to drop – that’s basic economics working for us budget travelers.

I love that this is a West Coast flight that doesn’t eat up your entire day. You’re looking at roughly 3 hours in the air, maybe 3.5 depending on winds. Short enough that you don’t need to stress about meal service or paying for entertainment, but long enough that you’ll want to bring a book or download a podcast.

Here’s something I learned after my third or fourth time flying this route: San Diego Airport is actually kind of amazing for budget travelers. It’s small, easy to navigate, and you can usually get there via public transit or a relatively cheap Uber. No dealing with LAX chaos or navigating multiple terminals. SeaTac on the other end is bigger but still manageable, and the light rail into downtown Seattle is only $3. These little things add up when you’re trying to keep costs down.

The flight usually leaves from Terminal 1 at SAN, which honestly has better food options than Terminal 2 anyway. I always grab a breakfast burrito from Puesto before my morning flights – probably not the most budget-conscious move, but we all have our weaknesses.

When to Book (And When to Definitely Not Book)

I’ve tracked this route obsessively enough that I’ve noticed some patterns. The sweet spot for booking is usually 4-7 weeks out. I know that’s a range, but it depends on the season. For summer travel, lean toward booking closer to 7-8 weeks out. For winter, you can sometimes wait until 4-5 weeks and still get decent prices.

Here’s what I’ve learned the hard way: booking super early doesn’t always save you money on this route. I once booked a flight four months in advance thinking I was being smart, paid $156, and then watched prices drop to $79 two months later. Could I have changed my flight? Sure, but Southwest’s change policy, while generous, doesn’t refund you the difference – they give you a credit. Lesson learned.

The absolute worst times to fly this route are holiday weekends, especially Thanksgiving, Christmas, and summer Fridays. I made the mistake of trying to fly up for the Fourth of July weekend in 2022 and paid $289 for a one-way ticket. One way! I was so annoyed with myself that I ended up driving up the coast instead on my next trip, which honestly turned into a pretty cool adventure, but that’s a different story.

Tuesday and Wednesday flights are your best friends. I’ve noticed that Saturday mid-morning flights can also be surprisingly cheap – I think because most people are either trying to maximize their weekend or they’ve already arrived at their destination. Thursday and Sunday? Those are business traveler and weekend warrior days, so prices jump.

One pattern I’ve noticed: if you’re flexible enough to take the 6am or the 10pm flights, you’ll often save $30-50 compared to the convenient 9am or 3pm options. I’m not gonna lie, those early morning flights are rough. I’ve definitely napped in the airport before a 6am boarding because it was easier than going home after dropping off my rental car. But fifty bucks is fifty bucks.

The Alaska vs. Southwest Debate (From Someone Who’s Flown Both Way Too Much)

Let me break down the two main players here because they’re really different animals, and which one is “better” totally depends on your situation.

Alaska Airlines is the dominant carrier on this route, and they run it like they own it – because basically, they kind of do. They’ve got flights leaving SAN for Seattle like every two hours during peak times. The pros? Lots of flexibility, you can earn miles if you fly frequently, and their credit card actually has some decent perks if you fly them regularly. I’ve got their card and the companion fare alone has saved me hundreds.

The cons? Alaska charges for pretty much everything beyond a personal item. Seat selection, checked bags, priority boarding – it all costs extra. But here’s my hack: if you don’t care where you sit, don’t pay for seat selection. You’ll get assigned a seat at check-in or at the gate, and honestly, the flight’s short enough that it doesn’t matter if you’re in row 7 or row 27.

Southwest is the other major player, and their pricing philosophy is totally different. What you see is what you get – no surprise fees at checkout. Two free checked bags (which is insane in 2024), no change fees, and their points system is actually pretty straightforward. I’ve earned enough points from their credit card welcome bonus to book two free flights on this route.

The downside? Sometimes their base fares are higher than Alaska’s even when you factor in bag fees. You’ve got to do the math for each specific trip. Also, Southwest doesn’t assign seats, so if you want to sit together with someone or you hate middle seats, you need to pay for Early Bird check-in or check in exactly 24 hours before your flight.

I flew Southwest to Seattle last October for a friend’s wedding, and even with Early Bird check-in, I paid less than Alaska’s cheapest option. But then in January, Alaska had a sale where their basic economy fare was $20 cheaper than Southwest even after I added a carry-on. It varies constantly, which is why you’ve got to check both.

My Actual Strategy for Snagging Deals

Okay, this is where I get a little nerdy about it, but this approach has saved me probably $2,000+ over the years on this route alone.

First, Google Flights is my starting point for everything. The calendar view where you can see prices across an entire month? That’s how I discovered that flying Wednesday to Sunday is usually $60 cheaper than Friday to Monday, even though it’s basically the same trip length. I’ve planned entire Seattle visits around cheap flight dates.

Set up price tracking alerts. Google Flights will email you when prices drop significantly for your dates. I’ve gotten alerts about flash sales that I would’ve completely missed otherwise. Just last month, I got an alert at 11pm about Alaska dropping prices to $69 each way for flights in March. Booked it from my phone in about three minutes.

Here’s something that feels obvious but took me embarrassingly long to figure out: always check both Google Flights AND the airline websites directly. Southwest doesn’t show up on Google Flights because they don’t play nice with aggregator sites. I’ve missed deals before because I only checked Google Flights and didn’t bother looking at Southwest’s website.

Also, I follow both Alaska and Southwest on social media and I’m on their email lists. I know, more email spam, whatever. But I’ve caught at least six major sales this way that I would’ve missed. They’ll usually announce sales on Tuesday or Wednesday, and you’ve got a limited window to book before the cheap seats are gone.

One time Alaska announced a sale at 9am on a Tuesday, and by 2pm most of the cheap seats to Seattle were already sold out for popular dates. The deals are real, but you’ve got to move fast.

The Hidden Costs That’ll Wreck Your Budget Deal

Let me tell you about the time I thought I’d found an amazing $52 flight to Seattle. I was so excited that I booked immediately without reading the fine print. Turns out, it was basic economy on Alaska, which meant no carry-on in the overhead bin – just a personal item. I ended up paying $35 to upgrade so I could bring my backpack. Suddenly my $52 flight was $87, which was pretty much the same as the standard economy fare I’d ignored.

Basic economy fares have gotten more restrictive over the past few years. You’re last to board, you get whatever seat is left, and your bag situation is limited. For a three-hour flight, I can usually make it work with just a backpack that fits under the seat, but you need to be realistic about what you’re packing.

Parking at San Diego Airport is another hidden cost that’ll sneak up on you. It’s like $32 a day for the closest lots. I’ve learned to either take an Uber, get dropped off, or use the smart traveler option if I’m gone for more than a few days. The trolley technically goes to the airport area now, which is great if you live near a trolley stop.

Also, think about timing and transportation on the Seattle end. SeaTac is farther from downtown Seattle than SAN is from downtown San Diego. The light rail is cheap but takes like 45 minutes to downtown. If you land at 11pm and you’re staying in Capitol Hill, that’s going to factor into your total trip cost and time.

Getting Creative: Alternative Strategies That Actually Work

I’m going to suggest something that sounds wild but has worked for me twice: sometimes it’s cheaper to book two one-way tickets on different airlines than to book a roundtrip on one airline. I know it sounds like more work, but hear me out.

Last spring, I found a Southwest flight from San Diego to Seattle for $79, but their return flight was $140. Meanwhile, Alaska had a return flight for $69. Booking them separately saved me $71. The only downside is if something goes wrong with one flight, the other airline doesn’t care – you’re on your own. But for a domestic route like this, I’m usually willing to take that risk.

Another thing I’ve done exactly once, and I’m not sure I’d recommend it but I’m sharing it anyway: I flew to Portland instead of Seattle because the fare was $40 cheaper, and then I took the Amtrak train from Portland to Seattle. The train was $35 and took 3.5 hours, but it was actually kind of scenic and I got some work done. Did I save money after factoring in the train ticket and extra time? Barely. But it was an experience.

The more practical alternative airport situation is considering Tijuana. If you live in South Bay, TIJ airport sometimes has cheap flights to the Pacific Northwest through various connecting cities. It’s more complicated and usually involves a connection, so it’s not my first choice for this route, but worth checking if San Diego prices are crazy high.

Flash Sales, Error Fares, and Being Ready to Pounce

Error fares on this route are super rare – like, I’ve seen maybe two in all the years I’ve been flying it. But flash sales? Those happen several times a year, and they’re legit.

Alaska typically has sales during the first or second week of January (when everyone’s broke from the holidays), and sometimes in September or October (shoulder season). Southwest’s sales are less predictable but they definitely happen. I caught a Southwest sale last year where San Diego to Seattle was $59 each way, and I booked flights for a trip I hadn’t even planned yet. Sometimes you see the deal and then figure out the trip.

The key to catching sales is being on airline email lists and following them on social media. Also, sites like Secret Flying and Google Flights’ deal features will sometimes highlight West Coast deals. I’ve got alerts set up for “deals from San Diego” and that’s how I’ve caught a few good ones.

When you see a price that seems too good to be true, check it immediately. I’m talking like, within the hour. I’ve hesitated on deals before thinking “I’ll book it after work” and by the time I got home, the sale was over or all the good dates were sold out.

Making This Work in Real Life

Here’s my honest take after flying this route more times than any person probably should: you can almost always find a reasonable fare if you’re even moderately flexible with your dates and willing to put in a tiny bit of effort.

My routine now is pretty simple. When I know I need to go to Seattle, I start checking prices about 6-8 weeks out. I set up price alerts. I check both Alaska and Southwest directly. I’m flexible with my exact travel dates by a few days if possible. And I don’t stress about finding the absolute rock-bottom price – if I can get a roundtrip for under $140, I’m pretty happy with that.

Under $100 roundtrip? That’s a great deal, and it happens more often than you’d think if you’re watching for it. Under $200? That’s pretty standard and totally acceptable. Over $250? Unless it’s a major holiday or you’re booking super last-minute, you’re probably not trying hard enough.

The beautiful part about this route is that it’s short, it’s competitive, and there are lots of flights. You’ve got options, which means you’ve got leverage. Airlines know they’re competing for customers here, so prices generally stay reasonable outside of peak times.

Last thing I’ll say: don’t let perfect be the enemy of good. I’ve definitely fallen into the trap of waiting for prices to drop more, only to watch them go up instead. If you find a price that fits your budget and works for your dates, just book it. You’ll drive yourself crazy trying to save an extra $15.

Now if you’ll excuse me, I need to go book another flight to Seattle. My cousin’s having a baby in June, and based on what I’m seeing, Tuesday flights are looking pretty good right about now.

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