Skills work as the unique stats of each playable character. Just as in GTA: SA, they are adjustable, however less variable and specific. There are eight categories of these skills and are listed as follows:
Special Ability: How long a Special Ability can remain active while fully charged. Store more charge for a greater maximum duration. Increasing is specific to each character.
Michael: Increase by scoring headshots, executing stealth takedowns, doing yoga sessions, and maintaining high speeds in vehicles as Michael.
Franklin: Increase by driving against the flow of traffic, narrowly avoiding collisions, and maintaining high speeds in vehicles as Franklin.
Trevor: Increase by taking damage, killing enemies, scoring headshots, and maintaining high speeds in vehicles as Trevor.
Stamina: How long you can run, swim, or cycle at full speed before losing health due to over-exertion. Increase this skill by practicing any of these disciplines. Every 18 yards you run or minute you swim, the stamina skill will raise by 1%.
Shooting: Your skill in handling firearms. Dampens recoil, reduces reload time, and increases ammo capacity. Increase this skill by landing hits on enemies, scoring headshots, and successfully completing Shooting Range challenges. You can raise your shooting skill with the gun challenges. It will raise at 3% for gold medals, 2% for silver medals and 1% for bronze medals.
Strength: Your physical power and resilience. Boosts melee damage, speeds up ladder climbing, improves sporting agility, and reduces damage taken from various sources. Increase by scoring hits in melee combat and practicing sports. For every 20 punches you land ,the strength skill will raise by 1%. Killing cows on the grapeseed farms gives you almost the same amount of percent for every 20 punches.
Stealth: Your skill at remaining undetected. Move quickly and quietly when in stealth mode. Increase this skill by remaining undetected and performing silent takedowns when in stealth mode. You can raise this skill by performing stealth takedowns and walking while in stealth mode.
Flying: Your skill in the cockpit of various aircraft. Take off, land, and manage turbulence more easily. Increase this skill by flying for sustained periods and succeeding at flight school challenges. Every 10 minutes spent flying the Flying skill will raise by 1%.
Driving: Your skill behind the wheel or handlebars. Pop wheelies more easily and retain more control while airborne. Increase this skill by holding wheelies and landing squarely out of big jumps. Every second spent in the air while driving the Driving skill will raise by 1%. Also every successful Stunt Jump gives you around of 2 or 3%.
Lung Capacity: How long you can hold your breath underwater before losing health. Remain submerged for longer. Increase this skill by diving and swimming underwater, and practicing yoga. Every minute spent swimming underwater the Lung Capacity skill will raise by 1%.
Online Skills
Save for the Special Skill, your character can build their seven main skills through the same methods. Your online stats are measured through your customizable character's Lifestyle. Stats are determined indirectly through choosing your character's allocation of hours spent on daily activities. These allocations have direct stat analogy relationships as listed bellow.
| Lifestyle | Increases | Decreases | Max Hours |
| Asleep | Stamina, Strength, Stealth, Lung Capacity | -- | 12 |
| With Friends & Family | Stamina, Strength | Shooting | 4 |
| Playing Sports & Working Out | Stamina, Strength, Lung Capacity | Shooting, Driving | 8 |
| Doing Legal Work | Stamina, Stealth, Flying | Driving | 10 |
| Sitting on the Couch | Flying, Driving | Stamina, Strength, Lung Capacity | 8 |
| Partying | Shooting, Stealth | Stamina, Strength, Flying, Lung Capacity | 8 |
| Doing Illegal Work | Driving, Shooting | Lung Capacity | 10 |
A starting character has 24 Hours to distribute among twelve activities. A minimum of 4 hours must be spent on sleep.
Character creation of a female.
These selections determine the stats of your character, as well as affecting his or her physique. As you lower some times and raise others, you will notice that your stats adjust accordingly. For instance, doing a lot of legal work will boost up your flying skills. It should be noted that hourly selections also effect starting clothing.
Five of the seven skill levels, which are displayed on the mission screen, have their own unique designation depending on what percentage each one is at as listed below:
Stamina
0-19%: Lethargic
20-39%: Out of Shape
40-59%: In Shape
60-79%:
80-100%: Tri-Athlete
Shooting
0-19%: Untrained
20-39%: Sprey-and-Prey
40-59%: Police Training
60-79%: Military Training
80-100%: Dead-Eye
Stealth
0-19%: Clumsy
20-39%: Loud
40-59%:
60-79%:
80-100%:
Flying
0-19%: Dangerous
20-39%: RC Pilot
40-59%:
60-79%:
80-100%:
Driving
0-19%:
20-39%: Sunday Driver
40-59%: Commuter
60-79%:
80-100%: Pro-Racer