Kayaking to Flat Island Kailua | A Family Guide to Popoia Island

Flat Island, known in Hawaiian as Popoiʻa, is a small offshore islet about a half mile paddle from Kailua Beach Park on Oahuʼs windward coast. At low tide you can land on a narrow sandy beach, walk the limestone perimeter, and watch wedge-tailed shearwaters and Bulwerʼs petrels going about their business overhead. Sea turtles forage in the shallow reef just south of the island. The paddle takes about 15 minutes on a calm day and the whole adventure is manageable for families with kids old enough to sit in a kayak. Dogs are not allowed on the island.

Hawaii’s Offshore Islets

I spent most of my free time in the ocean B.C. (before children) – swimming, snorkeling, kayaking, and surfing –  good memories! These days, I spend too much time looking at it longingly from shore while supervising two small children. But now that Mila is one year old, it’s time to take her kayaking to Flat Island. B.C. I was a biologist working for Bishop Museum and the University of Hawaii on the conservation of Hawaii’s offshore islets, or mini islands, that lie just offshore the main islands.

Being more isolated from human activity, development, and introduced pests has allowed rare native plants, seabirds, and the occasional cool bug to flourish. It’s like taking a little peak back in time to old Hawaii. Most of the offshore islets are either inaccessible or off-limits to protect native life. However, there are four offshore islands on Oahu worth a visit – Mokoli’i (Chinaman’s Hat), Mokuau’ia (Goat Island), Popoi’a (Flat Island), and Moku nui (The Mokes). Of those, Popoi’a is the easiest to access and the best option for families.

Kayaking to Flat Island – A Family Adventure

What is Flat Island?

Popoi’a, or Flat Island, is a 4-acre island that lies across from Kailua Beach Park on the east side of Oahu. As the nickname implies, it’s a flat island. So flat that you could potentially miss it with a glance at the bay.

The island is home to a handful of salt-tolerant native plant species and serves as the nesting ground for two species of seabird – the Wedge-tailed shearwater and smaller (adorable) Bulwer’s petrel. Both species lay eggs in the ground either by excavating burrows in the dirt or finding protected nooks in the islands craggy, limestone interior.

Packing List for Kayaking to Flat Island

The non-negotiables. A dry bag or heavy duty zip lock for your phone and keys. Water. Reef-safe sunscreen, a UV shirt, hat, and sunglasses. The sun on the water is intense and there’s no shade on the island. No aerosol spray.

On footwear. The island is limestone, which is rough and painful on bare feet. Reef shoes or slippers are not optional. Bring them for everyone including kids.

For little kids. Snacks. A dip net and bucket if your kids are into exploring. A leash on the kayak makes it easier to snorkel alongside without losing your boat.

Camera. Worth bringing. The seabirds are remarkably unbothered by humans and the views back to the Koolau Mountains from the water are some of the best in Kailua.

Getting to Flat Island

Before you head out, check local weather and surf conditions. Big swells and wind can make the paddle challenging even on a short crossing. Winds are normally onshore, which means heading out can be tough but coming back is usually easy.

Kayaking is the most practical option for families. You can also paddle or swim, though swimming is only recommended for experienced ocean swimmers. If you swim, bring a buoy. You’ll be outside the designated swim area in a busy bay shared with kayakers, canoes, paddleboards, and kiteboards, and visibility matters.

Launch from the stream at Kailua Beach Park, which is the most common starting point and easiest for families with kids and loaded kayaks. The boat ramp at the last parking access before Lanikai is another option if you prefer a cleaner entry (beware the boat ramp itself is very slippery).

Don’t have your own kayak or board? Kailua Beach Adventures rents across the street from the park and does a good job of educating visitors on ocean safety and natural history. They offer kayak rentals and guided or self-guided tours to Popoiʻa and Moku Nui. Note that no tours or rentals are permitted on Sundays.

The island is a seabird sanctuary. Dogs are not permitted.

Searching for Sea turtles (honu)

When you’re kayaking to Flat Island, keep an eye out for sea turtles. The area south (to the right if you’re facing the island from shore) of Flat Island tends to be a popular spot for Hawaiian green sea turtles. These endangered turtles spend the day foraging for limu (algae) among the shallow reefs in Kailua Bay. If ocean conditions are calm, you can paddle around looking for their little heads to pop up for breaths of air.

On the island

Land on the narrow, sandy beach facing Kailua Beach Park. Pull your kayak to dry land so the ocean doesn’t claim it but avoid damaging plants and burrows.

The distinct smell of the island comes partly from seabird guano and partly from plants – Chenoposium oahuense (a shrub in the Goosefoot family) or ʻĀweoweo in Hawaiian. ʻĀweoweo is both the name of the coastal shrub and a fish. When you crush the leaves of the plant, it smells like the fish!

Once on the island you can sit on the little beach and enjoy the view, explore the rocky shallows, or tour the perimeter of the island. The island is a seabird sanctuary so stay on the trail and out of middle of island to protect bird burrows and native plants. And leave dogs at home.

Can you snorkel around Flat Island?

Meh, not worth it. On a rare calm day you can snorkel around the coral heads off Lanikai Beach. The further out you go off Lanikai Beach, the more fish and live coral you will find, but go early before the sand gets stirred up and decreases visibility. And if you adventure out far, go with a buddy so they can hold your kayak while you snorkel. A leash on your kayak makes it easier to coordinate.

What to do after kayaking to Flat Island?

Grab a bite to eat in Kailua town

Kalapawai Market is the easiest stop for beach burgers, sandwiches, and snacks. Over Easy is worth the wait for a proper sit-down breakfast or brunch. Bob’s Pizza is right across the street from the beach and good for a casual lunch. Island Snow for shave ice, it’s in a local clothing store, which is exactly as Kailua as it sounds. Kono’s for kalua pork burritos if you’re hungry.

More adventures nearby

The Kaneohe Sandbar is a personal favorite on a calm day. A longer paddle but worth it. Lanikai Pillbox Trail before sunset gives you views of Flat Island from above. Hoomaluhia Botanical Gardens has the best picnic spot on the windward side.

Family Photos in Kailua

Kailua is home turf for me. I’ve been exploring this coastline with my own family for years and know every stretch of it; where the light lands, where the turtles show up, which spots work for toddlers and which ones are better for older kids. The entire Kailua coastline is beautiful for families and I love matching each family to the right spot. You can see what a morning here looks like here, here, and here. And if it looks like something your family would be into, here’s where to start.

Flat Island FAQs

Q: How far is it to kayak to Flat Island from Kailua?

A: About half a mile from Kailua Beach Park, which takes roughly 10 to 15 minutes on a calm day. Wind and current can make it harder. Check conditions before you go. The stream at Kailua Beach Park is the most common launch point for families.

Q: Can beginners kayak to Flat Island?

A: Yes, with reasonable conditions. The paddle is short and the bay is generally calm. Windy days are the main challenge. If you’re unsure, book a guided tour with Kailua Beach Adventures who will assess conditions for you.

Q: What wildlife can you see at Flat Island?

A: Wedge-tailed shearwaters and Bulwer’s petrels nest on the island and are remarkably unbothered by visitors. Sea turtles forage in the shallow reef just south of the island.

Q: What is the best time of year to kayak to Flat Island?

A: Summer months are best for calm conditions and the flattest water. This is also when the seabirds are most active — wedge-tailed shearwaters nest from May through October and you’ll see them coming and going from their burrows. Winter can bring bigger swells that make the crossing more challenging. Always check conditions before you go regardless of season.

Q: Do you need to rent a kayak to get to Flat Island?

A: No. You can kayak, paddleboard, or swim. Kayaking is the most practical option for families. Swimming is only recommended for experienced ocean swimmers. If you don’t have your own equipment, Kailua Beach Adventures rents kayaks and paddleboards and offers guided and self-guided tours. No tours or rentals on Sundays.