A chartplotter app shows your iPhone or iPad's GPS position moving on nautical charts. Most major apps are free to download, but you pay for the charts with a yearly subscription or an in-app purchase. For coastal boating, Navionics Boating has the most features of the apps we checked, at $49.99 a year for the US and Canada. For lakes and rivers, i-Boating includes USACE inland river maps and freshwater lake maps, with US chart packs listed at $19.99 to $29.99.
Look for these features:
In app listings, free usually means a free download or a trial. Check the in-app purchase list on the App Store page to see the actual price for your region. The prices below are listed on the US App Store as of this writing.
Navionics Boating is free to download and comes with a limited-time free trial. After the trial, charts and advanced features need a yearly auto-renewing subscription, listed at $49.99/year for US & Canada. It includes Navionics charts, SonarChart HD bathymetry and US NOAA charts (within the US & Canada and Caribbean coverages), and you can download charts for offline use. It also has Auto Guidance+ dock-to-dock routing, plotter sync, and AIS traffic display through a compatible Wi-Fi AIS receiver. The listing says Auto Guidance+ is for planning purposes only and does not replace safe navigation.
i-Boating is free with in-app purchases. US chart and fishing map packs are listed at $19.99 to $29.99. It uses NOAA vector charts, USACE inland river maps and freshwater lake maps. Features include depth contours, aids to navigation, routes, GPX/KML import and export, track recording, tides and currents for select regions, and AIS/NMEA support.
We could not confirm current prices for these apps, so check each App Store listing before you buy:
For a wider comparison, see our marine navigation apps roundup.
NOAA's Electronic Navigational Charts (ENCs) are free when you download them directly from Coast Survey. ENCs bought from IC-ENC or a value-added reseller carry a fee. NOAA uploads new ENC update cells every weekday evening, including safety-critical changes such as aids to navigation and newly found shoals.
NOAA completed its raster sunset program in December 2024, when it canceled the last of its 1,007 traditional paper (raster) charts. ENCs are now NOAA's primary nautical chart product. If an app still advertises NOAA raster (RNC) charts, those are no longer updated, so choose one that uses ENC vector data. More on this at free NOAA charts.
See lake chart coverage and USACE inland river charts for coverage by area.
iPhones have GPS. With iPads, it depends on the model. Apple's iPad tech specs list GPS/GNSS only on Wi-Fi + Cellular models. Wi-Fi-only models locate themselves using Wi-Fi. The Navionics listing says the same thing: a Wi-Fi-only tablet finds only an approximate position when connected to Wi-Fi, while a Wi-Fi + Cellular model works like a phone with GPS.
Your options on iPad:
More detail on our iPad page.
Federal chart carriage rules under 33 and 46 CFR apply to regulated commercial vessels. According to Practical Sailor, recreational boaters are not required to carry any charts, and USCG NVIC 01-16, which accepts electronic charts as equivalent to paper, does not change that.
In a 2022 recommendation to NOAA, its Hydrographic Services Review Panel called paper charts a valuable supplement to electronic systems during the transition to electronic charts. It urged NOAA to keep a paper backup option available, especially for small recreational boats.
A good backup is a paper chart, a chart book or a NOAA Custom Chart printout for your area. NOAA Custom Chart lets you create a paper chart from the latest ENC data and choose the paper size, scale, location and depth units (meters, feet or fathoms).
Helm is a native chart app for iPhone and iPad. Its charts are built from NOAA Electronic Navigational Chart data that the app reprocesses, and they are not an official NOAA product. Inland river charts come from US Army Corps of Engineers Inland ENC data. You can download chart packs for offline use under Settings > Offline charts (offline charts). Some features, such as CarPlay, need a subscription, so check the App Store for current pricing.
When the tide is known, the depth shown is the charted depth plus the current tide height above chart datum, which can be negative. When the depth is unknown, such as on land, in drying or unsurveyed areas, or on lakes with no current water level, the app shows a dash and never shows zero (how depth works). Routing plans against your boat's draft plus a safety margin and will not enter cells charted shallower than your draft. If a route can only get through by using part of the margin, those legs are drawn in red so you can check them against the chart. GPX import and export of waypoints, routes and tracks lets you bring marks across from Navionics, C-MAP, iNavX or a plotter (routes and GPX).
Helm does not connect to NMEA instruments or a hardware AIS receiver. It exchanges waypoints, routes and tracks as GPX files, and its AIS layer needs internet and only shows boats with transmitters. On a Wi-Fi-only iPad, Helm uses whatever location iPadOS provides. The app describes itself as an aid rather than the official chart and asks you to keep an official chart aboard.
Many are free to download, but most charge for US charts. Navionics Boating charges $49.99 a year for the US and Canada after its free trial, and i-Boating sells US chart packs for $19.99 to $29.99. Before you install a free app, check its in-app purchase list to see whether offline charts cost extra. NOAA's ENC data itself is free; see free NOAA charts.
Only with an external GPS receiver. Apple lists GPS/GNSS only on Wi-Fi + Cellular iPads, and a Wi-Fi-only iPad finds only an approximate position using Wi-Fi. Use a Wi-Fi + Cellular iPad, or pair a Bluetooth GPS receiver or a wired one that fits your iPad's port (USB-C on current models, Lightning on older ones).
Charts and GPS position will, if you download chart packs before you leave the dock. Navionics Boating, for example, lets you download charts for offline use. Internet-based layers such as online AIS and live water levels won't update without a signal.
Recreational boaters have no legal requirement to carry charts. A NOAA advisory panel (HSRP, 2022) called paper a valuable backup to electronic charts, so carry a paper chart, chart book or NOAA Custom Chart printout.
Free to download. Free trial included.
Helm Boating