Secchi vs COSEA
Price, ratings, monetisation and update history for both apps, side by side — 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.
COSEA
Document marine environments, coastal habitats, and species. Report on pollution, infrastructure, and the blue economy. Contribute data and photos to a collaborative map to help scientists understand marine factors and foster a healthy relationship between humans and the sea.
- Observe marine environments
- Document coastal habitats and species
- Report on pollution and infrastructure
- Add photos and data to a collaborative map
- Interact with the user community
- Build an environment notebook
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With COSEA you can observe your marine environment, document coastal habitats or species, do activities, and report on pollution, infrastructure, and the blue economy. COSEA is a collaborative, participatory, and community-driven project. With your contributions on the map and your activity in the app, you help scientists better understand the impacts and drivers of marine factors to protect and foster healthy relationship between humans and our seas. What can you do? In COSEA you can add your photos and data, aka "Spots, on the map. By submitting your observations and documentation, you can build up an environment notebook in your user profile and map your area. You can also interact, comment, and exchange with others in the user community, or simply respond to the contribution of a friend in the app with a heart & like. We all share a deep care for our seas and their resilience in changing times. With COSEA you can help strengthen a healthy relationship between humans and our oceans and learn more about marine protection, social impacts and sustainable use of natural resources. Open Project COSEA is an open project. We invite actors, stakeholders, environment groups, associations, youth projects, and others to co-use the COSEA App for observations, data collection, and community building. During the course of the projects, we will build innovative tools for you to enable independent and self-governed usage of COSEA for your marine and coastal activities. The COSEA App is running on the SPOTTERON Citizen Science Platform at www.spotteron.net
Screenshots
Verdict
The clearest difference is update cadence: COSEA at every 5 weeks against Secchi's every 7 months. COSEA also leads on iOS requirement (12.0 vs 15.6). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · 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, COSEA every 5 weeks. The most recent releases landed on September 23, 2026 and August 14, 2026 respectively.
| Parameter | Secchi | COSEA |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Number of ratings | — | 1 — better |
| Update frequency | Every 7 months | Every 5 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.6 | 12.0 — better |
| Further details — not scored | ||
| Size | 45 MB | 206 MB |
| Age rating | 4+ | 4+ |
| Developer | The Secchi Disk Foundation | SPOTTERON Gmbh |
In-app purchases
Secchi
No in-app purchases
COSEA
No in-app purchases









