There are many "Free" Tide/Moon Apps but most still require a fee for data access or future tides scanning.
Most require you're phones dreaded Global Roaming to be switched On for GPS and Tide data to be accessed by mobile. Some only give that days tide and some have glitches like leaving the GPS turned on when you close the App and running your Battery flat really fast. Some are just wobbly and slow.
Other "Free" Tide Apps hammer you with so much unsolicited advertising you will wish you paid the $2.50 for the ad-free version as the popups gobble your DL allowance.
Most people like the Curve Graph Tide display over Tabular info and most do not want their phone to make a call to a database every time they check the tide.
The one I use, "TIDE PLANNER" App for Phones. Free Download. Definitely for the Nerdy Skipper who likes to push buttons and experiment with strange Icons, has many pretty pages yet gives you local info as soon as it's opened.
With no instructions I was able to set it up for my area with a bit of fingerpoken.
TP is 20 MB because it has it's own Database and does not need to Connect and Download data so will work anywhere and give tide info instantly on any Global location. You can pay $5.00 and Download an Extension to quickly scan future Tides etc. Worth it since most Apps have an annual fee but don't give so much info such as Tide Flow maps for you're area.
Check it out here-->
http://www.tucabo.com/products/tides-planner/