Traveller - Porting Traveller to D&D5e, a thought experiment

On the 27th November 2025, Mongoose Publishing put the cat amongst the pigeons by announcing that they intended to bring out a D&D 5E edition of the game. 

This immediately led to panic (OMG are they abandoning Traveller's Engine) to vitriol (I hate 5E, why are you doing this) to more sanguine takes (This is good for the game as it will grow sales). Personally, I'm more in the latter box, and for me Traveller is the world's greatest roleplaying game. The previous D&D-engined Traveller T20 didn't harm the game and had some decent supplements (for example the Gateway campaign), plus it used High Guard as the basis for its starships.

Which led me to wonder how I would do this to maximise compatibility between the two editions.

1) Attributes

For these, I'd simply rename them in line with Traveller's conventions. You'd have to move the nobility thresholds for a 3D6 distribution, but otherwise it's pretty similar.

2) Hit Points

These are a sum of the physical attributes as usual; so a Traveller would start a little stronger on average. There would be limited opportunities to increase these.

3) Skills

I'd keep the skill levels in line with Traveller and they would come from your life path / career generation. If you have no skill in an area, you roll with disadvantage unless you have Jack-of-all-Trades (which may only ever be a single level or perhaps something like a feat that comes from a career path).

Need to reconsider how task chains would work when helping.

4) Careers and Terms

This is one of the big changes I'd make. The number of terms you serve in your career determines your level and the number of skills, mustering out elements, attribute mods you get. Serve two terms and you're Level 2, serve 9 terms and you're Level 9. Aging works as usual (you get to make a save based on a D20 DC target). Once you level up, that's the end of most skill development (it goes slowly like it does in core Traveller and you can accrue XP through training etc to get the next level).

I'd consider whether you get a general proficiency bonus in a career based on the levels you have in it. I think that would make sense, like a professional skill.

5) Combat / Guns etc.

I'd keep these the same stat-wise - hit points are on the same scale. Probably have some damage effect levels like core Traveller. Armour would affect damage as current with the only AC mods coming from dexterity.

6) Starships etc.

Again, I'd keep these the same and just adjust the skill rolls. 

7) Psionics

I'd likely treat these a bit like feats - you'd spend PSI to activate. May need to raise the cost slightly to align.

8) Conversion table

I'd have a simple table to map attributes between 2D6 and 3D6 scales.

Anyway, that's how I'd approach it from a top level perspective. A D&D 5E recognisable version that would be easy to hot swap material between system versions.

What would you do if you were designing a D&D 5E version?

9 December 2025