Which DLC should i do first?

[Seamless Zone Stalker]

Rising Tide or Echoes?

[Koby]

Echoes.

[♋ßLUE۫۰۪♋]

nonono. do the rising tides to get the new abilities and weps and do the echoes of the fallen so you have an excuse to use all the new abilities.

[mdair]

If plan to do all the side quests in Rising Tide then you will want to do Echoes first.

From a chronological story perspective it makes more sense. No spoilers but you will see if you do all the side quests in Rising.

Also if you have not leveled up to max then you want to do Echoes first to level up and get that HP. Rising was the harder of the two DLCs. In FF mode Echoes enemies stay in the 80s level, and in Rising they punch up into the 90s level and some at level 100.

[Seamless Zone Stalker]

Thanks for your answers!, seems doing echo first is the way to go but it seems rising gives you more abilities so i will go with that.

[jordyexists]

In my NG playthrough I did the order that Blue recommended. It makes The Rising Tide a bit more challenging, but considering the difficulty of the game, I don't consider that a negative thing. In my NG+ playthrough, I did Echoes first.
The level scaling is more natural if you do Echoes first, and Echoes does have some of the best trinkets in the game, so you could have made the argument to use Rising Tide to play around with those, but there's definitely more fun to be had with the eikonic abilities you get from Rising Tide.
The one thing I would recommend is that you check back at the quest hub in Rising Tide after you complete Echoes, as there is one bonus quest that unlocks if you've completed both Echoes and Rising Tide.
Enjoy!