Comparison

Secchi vs Sea Watcher

Price, ratings, monetisation and update history for both apps, side by side β€” with what reviewers say about each.

Head to head
About

Secchi

Features
Read full description

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.

About

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.

Highlights
  • 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
Read full description

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 don’t 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

Secchi4 screens
Sea Watcher4 screens

Verdict

The call

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

CostPrice Β· In-app purchases Β· Ads Β· Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

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.

Scorecard2 real differences Β· 6 level
Secchi versus Sea Watcher: the parameters behind the verdict, then further details
ParameterSecchiSea Watcher
PriceFreeFree
Positive reviewsβ€”100.0% of reviews
Update frequencyEvery 7 monthsEvery 6 weeks β€” better
AdsNoNo
In-app purchasesNoNo
Monetizationβ€”Free
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.613.0 β€” better
Further details β€” not scored
Size45 MB124 MB
Age rating4+4+
DeveloperThe Secchi Disk FoundationSea Watch Foundation - The Cetacean Monitoring Unit

In-app purchases

None

Secchi

No in-app purchases

None

Sea Watcher

No in-app purchases

Questions

Is Secchi free?
Secchi is free to download, with no in-app purchases.
Is Sea Watcher free?
Sea Watcher is free to download, with no in-app purchases.
Do Secchi or Sea Watcher have ads?
Neither Secchi nor Sea Watcher shows ads.
Which is updated more often, Secchi or Sea Watcher?
Secchi ships an update every 7 months, and Sea Watcher every 6 weeks. Most recently, Secchi was updated on October 10, 2026 and Sea Watcher on September 23, 2026.

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