Secchi vs Sea Watcher
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Secchi
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Climate change is threatening the phytoplankton that underpins the marine food chain. We must understand why before it's too late. Secchi enables you to take part in the Secchi Disk citizen science study and help collect essential data on the phytoplankton.
Sea Watcher
Log sightings of marine megafauna like whales, dolphins, and seals across UK and European waters. Identify species, record valuable data, and contribute to scientific understanding of marine life. Review your past sightings and see what others have observed.
- Log marine megafauna sightings
- Identify whales, dolphins, seals, and more
- Record sighting location and time
- Contribute to marine species research
- View past and recent sightings
- Learn about marine species
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Welcome to the Sea Watcher app! Here you can log your sightings of whales, dolphins, seals and other megafauna (basking sharks, ocean sunfish and sea turtles) anywhere in the UK and European waters. Whether walking along the coast path, watching from a clifftop or spotting from a boat, the Sea Watcher app will help you identify what you saw and record all the information that will be useful to help us understand more about all these marine species in the UK and European waters! The information you collect will be used to understand which species are seen where and when, and to highlight changes over time. It is also important to record when you are looking out for marine wildlife but donβt see any. You will be able to revisit your sightings as well as find out what others have seen around the British Isles in the last week, month or year. We hope you enjoy using this app and that it helps you to become a confident and regular Sea Watcher!
Screenshots
Verdict
The clearest difference is update cadence: Sea Watcher at every 6 weeks against Secchi's every 7 months. Sea Watcher also leads on iOS requirement (13.0 vs 15.6). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Secchi ships an update every 7 months, Sea Watcher every 6 weeks. The most recent releases landed on October 10, 2026 and September 23, 2026 respectively.
| Parameter | Secchi | Sea Watcher |
|---|---|---|
| Price | Free | Free |
| Positive reviews | β | 100.0% of reviews |
| Update frequency | Every 7 months | Every 6 weeks β better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | β | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.6 | 13.0 β better |
| Further details β not scored | ||
| Size | 45 MB | 124 MB |
| Age rating | 4+ | 4+ |
| Developer | The Secchi Disk Foundation | Sea Watch Foundation - The Cetacean Monitoring Unit |
In-app purchases
Secchi
No in-app purchases
Sea Watcher
No in-app purchases
Questions
Is Secchi free?
Is Sea Watcher free?
Do Secchi or Sea Watcher have ads?
Which is updated more often, Secchi or Sea Watcher?
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