Sumbi - Focus & Digital Detox

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About this app

The longer your phone rests, the deeper life becomes.
Sumbi is a digital detox app and focus timer that turns the time you spend away from your phone into a haenyeo's dive. Haenyeo are the free-diving sea women of Jeju, Korea, and this whole app grew out of their culture.

■ You choose just two things
Dive time, and breathing room.
Set how long you want to focus, and the dive begins. Breathing room is how long you're allowed to use other apps mid-dive, anywhere from 0 to 60 seconds. Use it all and the haenyeo runs out of breath, surfaces, and that dive ends there.
Phone calls are okay. Finish the call, come back, and your dive continues.

■ Stay deeper, meet rarer creatures
Hold on until the end and a shell will be waiting on the seafloor. Open it and you meet a creature. Clownfish live in the shallows. Green sea turtles swim further down. And if you go deep enough, aurora jellyfish drift through the abyss.
The longer the dive, the deeper the sea you reach. Studying, deep work, reading — any time you want to focus becomes a dive.

■ An ocean to tend, not a collection to finish
The creatures you meet live on in your ocean. Meet the same kind again and they school together. When the sea gets full, you release someone back to the open water.
There are no numbers or stats on this screen. It's made for gazing. And even after you let a creature go, the record of that meeting stays forever.

■ The sea is fair
Money doesn't buy the odds here. Neither do settings or friends. The only thing that moves the probability is time spent in the sea.
The chance of meeting an abyssal creature never goes above 8% on any dive, and that number is published as-is inside the app. There are no subscriptions and no loot boxes. If a creature wins you over, you can invite it for a small one-time price, and it's yours for good.

■ It's okay to fail
No dying trees. No red warnings. No guilt trips.
"You surfaced a little early. Your time in the sea is kept in your log."
That's the whole message. Catch your breath and dive again.

■ You don't have to dive alone
Link up with one person you trust and you'll get each other's dive news. Your buddy isn't there to watch you. They dive with you.

■ Before bed, the night sea
Try diving instead of scrolling before sleep. Start a dive between 9 p.m. and 6 a.m. and you'll meet different creatures, because some of them only wake at night. The abyss, though, is always night.
Putting your phone down at bedtime changes how deeply you sleep, too.

■ A log that reads like a diary
No scores, no rankings, no week-over-week screen time charts. Just the day's dive and the creatures you met that day, written down quietly.

■ Born from Jeju haenyeo culture
When a haenyeo surfaces after a dive, she lets out one long whistling breath called the sumbisori. That sound gave this app its name.
A haenyeo stays in the sea only as long as her breath allows, and Sumbi was built the same way. The Culture of Jeju Haenyeo was inscribed by UNESCO as Intangible Cultural Heritage in 2016. You can read the full story at https://sumbi.app

Sumbi is for you if
· You want to cut your screen time without an app yelling at you
· You need a focus timer for studying or deep work (a gentler Pomodoro, if you like)
· You're trying to break the scrolling-before-sleep habit
· You want a digital detox or dopamine detox with no streaks, scores, or shame

Sumbi measures success by the time you don't spend in the app.

Contact: sumbi@niceday.io
Put your phone down, a haenyeo dives. Digital detox & focus timer at sea.
Updated on
Oct 1, 2026
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Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • This app may collect these data types
    Personal info, Financial info and 2 others
  • Data is encrypted in transit
  • You can request that data be deleted

What’s new

You can now gift creatures from My Ocean.
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About the developer
(주)나이스데이
always@niceday.io
영등포구 양평로 91 5층 (양평동4가) 영등포구, 서울특별시 07208 South Korea
+82 10-4262-5386