I'm pretty sure there will be..
When we left off Hakuryuu said he's sorry, and left with Judar.. And Titus is back as a Magi, along with Gyokuen (the mother) saying it's a day of celebration - and that they will try summoning Father again..
So that combined with the fact that the manga got plenty of chapters, and that they are making two OVA's (one Maj, and the other Aughust) revolving around the origin of Sinbad - wich might lead to a spin off - all points towards a third season
The first season ran from October 2012 to Marts 2013 - and the second about a year later.. So if we're lucky might see a third season only a year from now
And the fact that the Kou empire and the Seven sea alliance are stille "fighting" (although Sinbad pulled som strings in the last episode) also indicated that there's still much to be resolved.