Is there a way to increase the number of workouts from 25?

There is not. However, if you use the schedule for your workouts they'll be synced to your watch and you will not have to worry about limits.

Also don't forget that if you go to the activity start screen and press up for options then training you can do intervals without a workout being predefined. This will take care of a lot of scenarios so 25 is actually pretty reasonable for real world use. I agree though, it's low for the spec of the watch, I suspect they did it on purpose to push you into using the platform as they intended with the schedule or ad-hoc mode workouts direct in the watch. They also have daily suggested workouts which I hadn't noticed before.

The tech company I work for often puts limits on things to drive user behaviour, it's a common tactic. I doubt it's an actual limitation just a number they picked.

lustyd said:

it's low for the spec of the watch

That could well be the case but really, who wants to scroll through an endless list of workouts to find the one required? It’s far better to keep that endless list in GC and schedule as needed. Even back in the day of Training Centre I’d never send too many workouts to the watch, preferring to schedule. 

The reality is it holds 25, but if you use the running plan of Greg for example, plus all the inbuilt ones its closer to 8.

I have 5 strength workouts that cover off different target body areas (Core, Upper, Legs, Power, mixed) and I have 50 pool swim programs around 3km. None of the swim programs are even close to the same, but the fact i can only have 3 on my watch is REALLY frustrating unless i log into connect first and schedule them just before I start then run a sync.

TheBrownDog said:

unless i log into connect first and schedule them just before I start

What's stopping the workouts being programmed several days in advance? Is it really desirable to scroll through dozens of workouts to find the one required? I too have dozens of swim workouts, countless run and bike workouts but would not want to have to scroll through the list to find the one I want just before I'm about to start a training session. Far easier to plan a little ahead and schedule them in the calendar.

I have a young family and work commitments. I have to fit training around that, no way I can schedule life that far ahead.

... and there might be another (a more comfortable) possibility, but it would require a tool for editing FIT files. The file limits for diverse folders are defined in the file //GARMIN/Device.fit, so editing the limit for the Workouts folder might work too. I did not test it (yet).

This looks quite promising.  Have you figured out a way to make the change to Device.fit?   I tried using the FIT2CSV tool but it didn't work.  Need someone with better HEX editing skills than me.