How Do Tides Affect Surfing?

Ever rocked up to the beach frothing for a wave, only to find it fat and slow? Or worse... closing out over shallow reef?

Yep... that's all because of the tides.

Tides are one of the biggest factors that determine whether a wave is magic or a mess, fun or frustrating. Checking them is one of the first things more experienced surfers do before paddling out. And once you get the hang of surfing tides, you stop showing up at random and start showing up at the right time.

Essentially, knowing all there is to know about how tides affect surfing (within reason) is one way to decode a surf forecast and score more epic sessions. Here's our rundown on tides and surfing.

What are tides?

Tides are the slow daily rise and fall of the ocean, caused mainly by the gravitational pull of the moon on the sea.

The sun has some influence, for sure, but the Moon does most of the work, tugging the water into bulges as the Earth spins beneath them. This is how tides are relevant to surfing:

• Most coastlines around the world get roughly two high tides and two low tides each day
• The sea level rises and falls over a cycle of about 6 to 6.5 hours between each high and low
• The timing shifts about 50 minutes later each day. A tide that's perfect at 7 AM today will be closer to 7:50 AM tomorrow

That last point is a goodie. When you can't remember what the tides are doing today but you know what they did yesterday, you can wager a decent guess. Our advice though? Check the tide tables and a surf forecast before you head out.

Want to learn how to read a surf forecast like a pro?

How does the tide change the waves?

The tide changes the waves you'll be surfing by changing the water levels over the reef or sandbars where the wave breaks. The depth of that water helps determine whether a wave breaks well and gives a great ride or breaks badly and breaks your heart in the process.

When a swell moves from deep ocean into shallow water near the shore, it slows down, stands tall and eventually pitches over to form a breaking wave. Add or remove a metre of water with the tide and you completely change how, where and with how much force that happens.

Same swell, same spot, totally different wave shape. All thanks to Seńor Tide.

Low tide vs high tide

Low tide

• This equates to less water over the break
• With a shallow bottom, waves tend to jack up faster and steeper
• This can make them hollow and punchy... but it can also cause them to close out (break all at once instead of peeling) and expose rock or reef
• On the shallow reefs around Bali, a dead low can turn a fun wave into a sketchy one reeeeal quick

High tide

• This means more water over the break
• Waves are usually fuller and softer
• They're less likely to close out because there's more water to hold their shape
• The catch? Too much water and some spots go fat and slow with no energy to push you

Neither one is the best tide across the board. Every local break has its own preference. The skill is knowing which is which. That's where our trusted surf guides and coaches enter the scene.

Incoming vs outgoing tide

Time to take your Tides IQ up a notch! Because in addition to how high or low the tide is, it's also important to note the direction it's moving too.

Incoming tide

• An incoming tide is water pushing in toward the shoreline
• That incoming current tends to add a bit of size and consistency, so the waves often seem better and more organised
• You'll sometimes get faster waves with more power and push and therefore more speed

Outgoing tide

• An outgoing tide (also called a dropping tide) is water draining back out
• This can make surf conditions more inconsistent and rippy and hard to ride
• As a rough rule that works at loads of waves... a mid-tide rising toward high (plus a couple of hours around high tide) is often the safest bet for fun, forgiving waves
• It's a great default when you're not sure

Spring tides vs neap tides (the moon phase thing)

This is maybe not super relevant to your average Joe and Jane beginner surfer, but it's good to know nonetheless.

Spring tides

• These happen around the full moon and new moon, when the sun and moon line up and their gravity pulls together
• You get a bigger tidal range, higher highs and lower lows, sometimes verging on extreme tides
• You often get bigger, more powerful surf too
• The water also moves faster, so the good window at each spot can be shorter

Neap tides

• Neap tides happen around the half moons (the moon's quarter phases), when the sun and moon pull at right angles and partly cancel out
• The range is smaller, the water moves less, and the waves are generally gentler
• This can deliver mellow small waves that can be lovely for beginners

The whole cycle runs about a month, swinging between big spring tides and calmer neaps roughly every two weeks.

Tides don't work alone

Tides are a big factor, but they're one piece of the puzzle. To read the ocean like a prepared surfer, you factor in a few things at once:

• Swell: The size, direction and period of the swell. Swells with long periods (waves that have travelled a long way from distant storms) pack more energy and can make a spot work on a tide it normally wouldn't
• Wind: Light or offshore wind grooms clean waves, while strong winds and onshore wind chop them to bits
• Weather and season: Weather conditions and seasonal swell patterns shape what's on offer through the year, so the best waves at a spot come and go with the calendar
• Temperature: Not a wave factor, but it shapes your surf session. In cold temperatures you'll want the right wetsuit; in tropical zones like Bali and the Bukit Peninsula you won't. Either way, check the forecast so you're not caught out

The takeaway: Tides matter, but they always combine with swell and wind to create the final wave conditions.

Why tides matter even more over reef

If you're used to beach breaks back home, whether that's San Diego or Ericeira or Hossegor or the Gold Coast or another local spot, Bali will teach you to respect the tides quickly because most of the classic waves here break over reef.

Over sand, a bad-tide closeout just means a clumsy wipeout. Over shallow reef at low tide, it can mean cuts and dings, so here the tide isn't only about wave quality... it's a safety call too.

This is a big reason beginners are often steered toward mellow, more forgiving spots and higher, pushing tides while they're learning, and away from shallow reefs on a draining low.

Around the Bukit, you'll quickly notice each wave has its own tide.

Some only switch on at dead low. Others need plenty of water to work at all. A few close out or get dangerous at the wrong stage. That's not something to memorise from an article. It's exactly the local knowledge our coaches or guides give you in your first session.

How to actually use tides

You don't need a science degree. You need a simple habit that turns the tide to your advantage:

1. Check the tide tables and surf forecast for the day before you plan your session
2. Match the tide to the spot. Ask a local, a coach or our surf camp which tide suits the wave you want to surf. Every spot has a slight variation
3. Factor in the swell and wind. A bigger swell can make a wave work on a tide it normally wouldn't and wind can undo a perfect tide. They all work together
4. Watch and learn. Sit and watch a spot change over the course of a few hours, from low to high, ideally at dawn or into sunset (with a cold drink in hand). Once you've seen it shift with your own eyes, it's easier to decode

Do this a few times and reading the tide stops being a chore. It becomes second nature... part of how you sniff out the best wave of the day and get the most from your surfing experience.

FAQs

Q. Is it better to surf at high tide or low tide?

It depends entirely on the spot. Low tide makes waves shallower, steeper and hollower (but more likely to close out or expose reef). High tide makes them fuller, softer and less likely to close out. Many spots surf best on a mid-tide pushing toward high.

Q. What tide is best for beginners?

Generally a higher, incoming tide at a mellow beach or sand-bottom break. There's more water over the bottom, the waves are softer and more forgiving and there's far less risk of hitting shallow reef.

Q. Why do the best waves happen at a different time each day?

Because the tide cycle shifts about 50 minutes later every day. Yesterday's perfect tide time won't be today's, which is why you always check fresh tide tables. You can go off memory too... so long as you remember yesterday or the day before tide times and do the math properly.

Q. What's the difference between spring and neap tides?

Spring tides (around the full and new moon) have a bigger range and often bigger, more powerful waves. Neap tides (around the half moons) have a smaller range and gentler waves. They alternate roughly every two weeks.

Q. Does an incoming tide really make waves better?

Often, yes. A rising incoming tide pushes water toward shore, which can add a little size and consistency, so many spots feel better on the push than on a dropping, outgoing tide. It's not a hard rule, but it's a solid starting assumption.

Ready to learn the tides on real Bali waves?

The fastest way to understand tides is to surf a spot every day and watch it change with a coach who already knows its moods. Which is why learning with a surf camp (wink wink, nudge nudge) is the way to go.

Want to stop guessing and start reading the ocean like a local?

Come surf with us in Uluwatu! The Bukit Peninsula has a spot working on almost every tide and our local coaches will teach you exactly which wave to surf and when. See you in the lineup.