OSRS Ammonite Crabs Guide: XP Rates & Aggroing

Ammonite Crabs are one of the most popular AFK training spots in Old School RuneScape. With low Defence, high hitpoints, and very low damage, they’re ideal for both low- and mid-level players looking to train melee, ranged or magic skill efficiently, although the 1 defense pures, have to be careful with their hitpoints and wear the highest defence armour they have. Killing ammonite crabs also provides slightly higher experience rates than sand crabs due to their hitpoint of 100, resulting in 400 experience for each kill. In this guide, we will take a look at this, also cover locations, requirements, how to aggro, and XP rates, and compare with other monsters.

Requirements

•   Bone Voyage quest completion (mandatory).
  
• No combat requirements, but decent combat stats are highly recommended
• Basic combat gear. Some defence is recommended but not required. 

Ammonite Crabs are combat level 25, max hit 1, and have 100 HP, making them tanky but harmless.

Location

Ammonite Crabs are found exclusively on Fossil Island. There are several ways to get here, but we'll cover the most efficient ones here.

Here are the locations on Fossil Island where you can kill ammonite crabs: 

Mushroom Forest

This is the largest and most noticeable part of the island, and it is filled with level 109 Ancient Zygomiters in mushroom form. It is also well-known for its hardwood tree farming and Herblore. This is the best location for killing Ammonite crabs, but it is frequently crowded. This location contains up to 28 spawns of level 25 ammonite crabs. Running north west from museum camp (where you are dropped off from the ship from the digsite) is the quickest way to get here.

Fossil Island Volcano

This volcano can be found on the eastern side of the fossil island, and it occasionally erupts and spews lava, which can cause minor damage to your character. There are approximately four Ammonite crab spawns in this area.

Wyvern cave

This cave is popular amongst players that train slayer because it is filled with Wyverns, but it also contains ammonite crabs. To get to this cave, travel to Fossil Island via the Barge, then run east, then south-east into the cave, which contains only 7 spawns of level 25 ammonite crabs. 

Getting There

•   Digsite Pendant (best option): Teleports directly to Fossil Island after quest completion. It can be made by enchanting a ruby necklace with a level-3 enchant; all that is required to make or use it is the completion of the Dig Site quest and the spell learned from one of the archaeologists.

Tip: Instead of purchasing multiple necklaces, if you have 82 construction, a curator's medallion can be mounted in a house portal nexus to create a mounted digsite pendant, which grants you unlimited teleports to the digsite.

•   Varrock → Barge Guard: Travel by boat from thedDigsite after completing Bone Voyage.
•   Mushroom Teleports (Fossil Island transport system): Unlock mush trees to quickly reach NW or SE crab spots.

Training method

Ammonite crabs are aggressive, so if you get too close to them, they will attack you. First, you must hop worlds until you find a good spot with two or three Ammonite crab spawns close to a single tile. Once you've found a good spot, stand in that tile so that both of them can attack you at the same time, then enable auto-retaliate. When your combat level increases and you can kill the two Ammonite crabs faster, you should switch to the three ammonite crab spots. If the crabs stop attacking you, you would need to reaggro them by following the section below.

How to aggro Ammonite crabs

Ammonite Crabs remain aggressive for about 10 minutes before becoming passive.
To re-aggro them:

• Run far enough away (usually a screen or two off, e.g., near the Fossil Island volcano) and return.
• They’ll attack you again, allowing you to AFK for another cycle.

Tip: If you are using Runelite, you can use the aggressive monsters plugin, which shows you the timer of how much time you have left before they stop attacking you because they are aggressive.

  EXP Rates

Ammonite crabs are known to provide the highest experience rates of any crab in OSRS. When training with Ammonite crabs, here are the different experience rates that you should expect depending on your combat method.

  Experience rates when training melee

You can get about 5,000 average XP per hour from levels 1 to 20.

From levels 20 to 40, you can expect to gain about 12,000 XP per hour on average.

From levels 40 to 60, you can gain up to 30,000 XP per hour by using a dragon scimitar.

If you decide to kill ammonite crabs until you reach 99 melee combat, you should start gaining 60,000-80,000 experience per hour if you use the best combat gear you can find.  

• Low levels (1-50): ~10–40k XP/hr
• Mid-levels (60–80): ~40–70k XP/hr
• High levels (90+): ~70–100k XP/hr

   Experience rates when training ranged

Beginning levels are quite quick when training at ammonite crabs, and when you get to 70 ranged, you can expect to gain 50,000 experience per hour, and as you get closer to 99 ranged, you can gain up to 90,000 experience per hour.

• Low Levels (1-50): ~15-30k XP/hr
• Mid Levels (50-75) ~30-50k XP/hr
• High Levels (75+) ~50-100k XP/hr

  Experience rates when training magic

When training magic at ammonite crabs, you should expect about up to 30,000-70,000 experience per hour from level 60 to 99 magic. The recommended spell to use is the fire wave, but this method is expensive, and it may be worth considering options that are similar in cost but have faster experience rates, such as ice bursting/barrage maniacal monkeys.

• Low levels (1-60): ~10–30k XP/hr
• Mid levels (60–80): ~30–50k XP/hr
• High levels (90+): ~50–70k XP/hr

Differences between Sand crabs and Ammonite crabs

Sand crabs can be found west of the woodcutting guild, as well as on Crabclaw Isle, which is less crowded. Sand crabs, like Ammonite crabs, lack combat stats, which means they cannot inflict damage on your character at a certain defence level. The following are the distinctions between Sand crabs and Ammonite crabs:

Verdict: Ammonite Crabs offer better XP rates thanks to their higher HP, but require Bone Voyage and can still be crowded.

Differences between Ammonite crabs and Rock crabs

Rock crabs are one of the three types of crabs found in Oldschool Runescape, Although they might look similar in terms of appearance and combat stats, they are found in completely different locations. Rock crabs are found mainly on Waterbirth Island and are also smaller. Some other differences between Rock crabs and Ammonite crabs include:

Verdict: Ammonite Crabs offer better XP rates thanks to their higher HP, but require Bone Voyage and can still be crowded and hard to find empty spots.

Differences between Gemstone Crabs and Ammonite Crabs

If you already have access to Gemstone Crab content and meet the requirements, it is generally superior in real use to Ammonite Crabs for most players (especially for prolonged AFK sessions).

Verdict: Gemstone Crabs are better, although they give less exp in percentage in the long run, it is more convenient to make Gemstone Crabs since they do not have time intervals to attack between one crab and another, like the ammonite, etc. 

Gemstone Crab XP reduction

Yes, Gemstone Crab XP rates have been reduced by 12.5%, but they remain favorable due to consistent, AFK combat with no downtime for overkill damage. The reduced rate is compensated by the constant 10-minute attack intervals, which can lead to higher overall experience per hour, especially compared to other methods where experience is lost through overkill damage or downtime. 

XP per damage: You will get 87.5% of the usual experience per damage dealt. 

For example, (1) damage is now worth (3.5) experience instead of (4).

Drops

  Weapons
Iron pickaxe (1/25.6)

  Fossilised currency
Numulite ×4 (1/4.414), Numulite ×2 (1/16), Numulite ×8 (1/21.33)

  Materials
Volcanic ash (1/21.33), Tin ore ×3 (1/32), Iron ore (1/64), Opal bolt tips ×5 (1/64), Coal ×2 (1/64), Copper ore ×3 (1/64)

  Oysters and Seaweed
Oyster ×2 (1/10.67), Oyster (1/14.22), Seaweed ×1–2 (1/16), Empty oyster (1/42.67), Seaweed ×5 (1/64), Edible seaweed ×2 (1/64), Oyster pearl (1/128), Empty oyster ×3 (1/128)

  Other
Fishing bait ×10 (1/64), Calcite (1/128), Pyrophosphite (1/128), Seaweed spore ×2 (1/128), Casket (1/128)

  Gem drop table
Uncut sapphire (1/512; 1/260), Uncut emerald (1/1,024; 1/520), Uncut ruby (1/2,048; 1/1,040), Chaos talisman (1/5,461; 1/2,773), Nature talisman (1/5,461; 1/2,773), Uncut diamond (1/8,192; 1/4,160), Loop half of key (1/16,384; 1/8,320), Tooth half of key (1/16,384; 1/8,320), Rune javelin ×5 (1/16,384; 1/8,320), Rune spear (1/262,144; 1/15,600), Shield left half (1/524,288; 1/31,200), Dragon spear (1/699,051; 1/41,600)

  Tertiary
Numulite ×5–14 (1/6.481), Unidentified small fossil (1/116.7), Clue scroll (easy) (1/128), Unidentified medium fossil (1/233.3), Unidentified large fossil (1/291.7), Unidentified rare fossil (1/1,167)

Since profit is negligible, you should train here purely for combat XP.

Conclusion

Ammonite Crabs are one of the best AFK combat training spots in OSRS for players who’ve unlocked Fossil Island. They have low defence in melee, are harmless, and provide some of the best XP/hr AFKable in OSRS. Although if you want more EXP per hour, more AFK and better experience, you can go for the Gemstone Crabs

If you’re looking for low-effort combat training, unlock Bone Voyage, bring your best AFK setup, and head to the southeast beach for the most reliable spots.