# SentinelTDS vs High Tide Chart

The clearest difference is in-app purchases: SentinelTDS at none against High Tide Chart's 1. SentinelTDS also leads on ads (none vs shown). High Tide Chart's advantage is update cadence (every 2 months vs every 6 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. High Tide Chart sells 1 in-app purchase, starting at $3.99 per month. SentinelTDS asks for nothing beyond the download.

SentinelTDS ships an update every 6 months, High Tide Chart every 2 months. The most recent releases landed on October 24, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | SentinelTDS | High Tide Chart |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.5 (2 ratings)](https://appshunter.io/ios/app/high-tide-chart/id6753727747/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 6 months | **Every 2 months** |
| Monetization | — | Free with in-app purchases |
| Size | 4 MB | 52 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | +4 |
| Developer | [Técnicas de Soft, SA](https://appshunter.io/developer/1201704143) | [Web Evolui](https://appshunter.io/developer/1476642695) |

## What reviewers say

### SentinelTDS

[App page](https://appshunter.io/ios/app/sentineltds/id1201704144)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### High Tide Chart

[App page](https://appshunter.io/ios/app/high-tide-chart/id6753727747)

Get accurate tide times and tide charts for any location. Plan beach days, fishing trips, or boating excursions with real-time sea level visualization and daily schedules. Ideal for coastal activities and marine enthusiasts.

**Highlights:** Accurate tide table for selected locations, Real-time tide chart with sea level visualization, Daily high and low tide times, Fast, simple, and user-friendly interface, Ideal for beach, fishing, surfing, and boating

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| High Tide Premium | $3.99 | per month |


## Frequently asked questions

### Is SentinelTDS free?

SentinelTDS is free to download, with no in-app purchases.

### Is High Tide Chart free?

High Tide Chart is free to download, with in-app purchases available.

### Do SentinelTDS or High Tide Chart have ads?

High Tide Chart shows ads; SentinelTDS does not.

### Which is updated more often, SentinelTDS or High Tide Chart?

SentinelTDS ships an update every 6 months, and High Tide Chart every 2 months. Most recently, SentinelTDS was updated on October 24, 2026 and High Tide Chart on October 23, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*