Catching Pokémon is at the core of every trainer’s journey—but some Pokémon in Generation III and IV can turn that adventure into a true test of patience. In this article, we rank the top 10 hardest Pokémon to catch in Gen III–IV based on their catch rate probability at full HP—with no status effects and a standard Poké Ball.
Understanding which Pokémon are hardest to catch can help you prepare strategies using status effects, advanced Poké Balls, or even specialized moves like False Swipe.
Table of Contents
What Determines Catch Difficulty?
Catch rate in Pokémon is an internal stat ranging from 3 (extremely hard) to 255 (very easy). Gen III and IV use a specific formula that factors in:
- Pokémon’s base Catch Rate
- Current vs. Max HP
- Type of Poké Ball
- Status condition
In this ranking, we assume:
- The Pokémon is at full HP
- No status effect
- Standard Poké Ball is used
This reflects the lowest natural probability of capture.
Summary Table: Top 10 Hardest Pokémon to Catch in Gen III–IV
| Rank | Pokémon | Catch Rate | Catch Probability (Full HP, Poké Ball) |
|---|---|---|---|
| 1 | Beldum | 3 | ~1.6% |
| 2 | Ho-Oh / Lugia | 3 | ~1.6% |
| 3 | Articuno / Zapdos / Moltres | 3 | ~1.6% |
| 4 | Registeel / Regice / Regirock | 3 | ~1.6% |
| 5 | Kyogre / Groudon | 5 | ~2.3% |
| 6 | Deoxys | 3 | ~1.6% |
| 7 | Rayquaza | 3 | ~1.6% |
| 8 | Suicune / Raikou / Entei | 3 | ~1.6% |
| 9 | Mewtwo | 3 | ~1.6% |
| 10 | Latios / Latias | 3 | ~1.6% |
10. Latios / Latias
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
These roaming legendaries from Pokémon Ruby, Sapphire, and Emerald are elusive in every sense. Their low base catch rate combined with their tendency to flee battle makes them a major challenge.
🡆 Tip: Use a Master Ball or trap them with Mean Look.
9. Mewtwo
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
Although Mewtwo originally appeared in Gen I, it makes a return in FireRed and LeafGreen. With its immense power and minimal catch probability, going in without a strategy is a mistake.
🡆 Use a combination of Sleep and Ultra Balls to boost odds.
8. Suicune / Raikou / Entei
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
These Johto beasts appear in FireRed/LeafGreen depending on your starter. Like Latios and Latias, they roam, which complicates the process.
🡆 Use a Fast Ball in Gen IV (HeartGold/SoulSilver) for a slight edge.
Read also: Best Poké Balls for Each Pokémon Type: Catch Pokémon Smarter
7. Rayquaza
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
This Emerald mascot is one of the most iconic dragons in Pokémon history. He appears at Level 70 and can devastate your team if you’re not ready.
🡆 Best strategy: bring a False Swiper and someone who can induce Sleep.
6. Deoxys
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
Only obtainable via event in Gen III, Deoxys is both rare and difficult to catch. Each form (Attack, Defense, Speed, and Normal) appears in different games, but all share the same abysmal catch rate.
🡆 Pair Timer Balls with Sleep to boost your odds in longer battles.
5. Kyogre / Groudon
Base Catch Rate: 5
Catch Probability at Full HP: ~2.3%
While slightly easier than the Pokémon above, these weather titans still pose a hefty challenge. You’ll meet them in the Cave of Origin (Kyogre in Sapphire, Groudon in Ruby).
🡆 Timer Balls become extremely effective after a few turns.
4. Registeel / Regice / Regirock
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
The Regi trio are hidden deep within puzzles in Gen III. Once you get through the braille and mechanics, you’ll still need to tackle their low catch rate.
🡆 Dusk Balls are optimal if you fight them in caves or at night.
3. Articuno / Zapdos / Moltres
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
Reintroduced in FireRed and LeafGreen, these classic birds are tough to catch. You’ll need perseverance, plenty of balls, and status infliction.
🡆 Tip: Save before each battle—resetting is your friend here.
2. Ho-Oh / Lugia
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
Both legendary birds from Gen II make appearances in Colosseum, XD: Gale of Darkness, and later HeartGold/SoulSilver. Regardless of the game, catching them at full HP with a basic Poké Ball is a near impossibility.
🡆 Use Ultra Balls or Net Balls (for Lugia) once HP is reduced and status applied.
1. Beldum
Base Catch Rate: 3
Catch Probability at Full HP: ~1.6%
Surprised? Beldum tops this list not because it’s legendary—but because it’s deceptively hard. Found in Steven’s house in Mossdeep City after you beat the game, this pseudo-legendary is just as difficult to catch as Mewtwo or Rayquaza—but only knows Take Down, which causes recoil damage.
🡆 The biggest risk? Beldum faints itself before you catch it.
🡆 Try using Ghost-types to avoid damage and False Swipe to bring it to 1 HP.
Final Tips for Catching the Uncatchable
To improve your odds when facing these Pokémon:
- Put them to Sleep (Sleep > Paralysis > Burn/Poison)
- Use False Swipe to reduce HP to 1
- Bring Dusk Balls, Ultra Balls, or Timer Balls
- Save before the encounter
Conclusion
Capturing legendary or rare Pokémon in Generations III and IV can feel like a gamble. But with the right tools, preparation, and knowledge of catch rate mechanics, you can turn frustration into victory. The Pokémon in this list are among the toughest—but they’re also the most rewarding to catch.
Train smart, save often, and may your Ultra Balls never fail!
