GTA San Andreas and GTA Vice City occur before GTA 3, so some characters will inevitably appear in both games.
GTA 3 canonically took place in 2001. GTA San Andreas and GTA Vice City took place in 1992 and 1986, respectively. Hence, it shouldn't be surprising that some GTA 3 characters have roles in other games. In some cases, these roles are entirely different from their GTA 3 counterparts.
These characters tend to be easily recognizable to GTA 3 fans. It isn't just cameos, either. What helps is that their appearances in later games tend to add to the lore of the 3D universe.
Five GTA 3 characters that show up in GTA Vice City and GTA San Andreas
5) Claude (GTA San Andreas)
GTA 3's main protagonist shows up as a minor character in GTA San Andreas. More specifically, he appears in two missions (Wu Zi Mu and Farewell, My Love). In his first appearance, he's merely a background character. Hence, it's easy to miss him.
However, GTA San Andreas players won't miss him in his second appearance. He's shown with Catalina, thus starting their relationship. It ends in a disaster, but CJ does acquire Claude's old, beat-down garage.
Catalina then taunts CJ about her love for Claude in various phone calls throughout the game.
4) Salvatore Leone (GTA San Andreas)
One of GTA 3's most important antagonists plays a small yet memorable role in GTA San Andreas. He appears in the Las Venturas section of the game and is primarily involved in some casino activities. He gives CJ a few missions in the main storyline.
Salvatore Leone is also seen meeting his love interest (Maria) in the game. CJ can optionally rob Caligula's Palace, which infuriates Salvatore Leone. The players never saw him again afterward in GTA San Andreas.
3) Donald Love (GTA Vice City)
Donald Love plays an excruciatingly minor role in GTA Vice City compared to his role in GTA 3. In this game, he is an apprentice to Avery Carrington. He learns various business strategies under him. Donald even quotes one of Avery's lines in GTA 3.
GTA Liberty City Stories fans should know that Donald Love had Toni kill Avery. Donald Love is a cannibal, so it's a tragic end to their mentor-student relationship. Donald Love's disappearance from GTA 3 is the last time players see him in person in the series.
2) Catalina (GTA San Andreas)
Catalina plays a significant role in GTA San Andreas. She gives CJ nearly half a dozen missions before betraying him. Her relationship with CJ is twisted, yet Claude is none the wiser.
Most GTA San Andreas players will remember several of Catalina's annoying phone calls. These calls become more desperate as CJ progresses through the game.
1) Phil Cassidy (GTA Vice City)
Phil Cassidy has appeared in most 3D universe games. He plays a minor role in GTA 3, but his GTA Vice City counterpart is far more significant. First, he's involved in the primary heist of the game (The Job).
Second, he gives several missions to Tommy Vercetti. One of these missions involves him losing his arm, which is one of his defining physical characteristics. Like with Donald Love, Phil Cassidy has changed the most between the games.
After all, GTA Vice City was a long time ago compared to GTA San Andreas.
Note: This article reflects the writer's personal views.