diff --git a/api/src/main/java/org/geysermc/geyser/api/item/custom/CustomItemData.java b/api/src/main/java/org/geysermc/geyser/api/item/custom/CustomItemData.java
index 0f80aae0a..2fab74dd4 100644
--- a/api/src/main/java/org/geysermc/geyser/api/item/custom/CustomItemData.java
+++ b/api/src/main/java/org/geysermc/geyser/api/item/custom/CustomItemData.java
@@ -142,11 +142,11 @@ public interface CustomItemData {
      * Gets the attack damage of the item.
      * This is purely visual, and only applied to tools
      *
-     * <p>Returns 0 if not set. When 0, Geyser takes the Java item attack damage when based on a vanilla item, or uses 0 when porting a modded item.</p>
+     * <p>Returns -1 if not set. When not set, Geyser takes the Java item attack damage when based on a vanilla item, or uses 0 when porting a modded item.</p>
      *
      * @return the attack damage of the item
      */
-    @NonNegative int attackDamage();
+    int attackDamage();
 
     /**
      * Gets the armor type of the item.
@@ -161,11 +161,13 @@ public interface CustomItemData {
     /**
      * Gets the armor protection value of the item.
      *
-     * <p>Only has a function when {@link CustomItemData#armorType} is set.</p>
+     * <p>Only has a function when {@link CustomItemData#armorType} is set, or when the Java item is an armor item (when based on a vanilla item).</p>
+     *
+     * <p>Returns -1 if not set. When not set, Geyser takes the Java item protection value when based on a vanilla item, or uses 0 when porting a modded item.</p>
      *
      * @return the armor protection value of the item
      */
-    @NonNegative int protectionValue();
+    int protectionValue();
 
     /**
      * Gets if the item is a hat. This is used to determine if the item should be rendered on the player's head, and
diff --git a/core/src/main/java/org/geysermc/geyser/item/GeyserCustomItemData.java b/core/src/main/java/org/geysermc/geyser/item/GeyserCustomItemData.java
index 4eaddaa6b..28fedb145 100644
--- a/core/src/main/java/org/geysermc/geyser/item/GeyserCustomItemData.java
+++ b/core/src/main/java/org/geysermc/geyser/item/GeyserCustomItemData.java
@@ -204,9 +204,9 @@ public class GeyserCustomItemData implements CustomItemData {
         protected Set<String> tags = new HashSet<>();
         private int stackSize = 0;
         private int maxDamage = -1;
-        private int attackDamage = 0;
+        private int attackDamage = -1;
         private String armorType = null;
-        private int protectionValue = 0;
+        private int protectionValue = -1;
         private boolean hat = false;
         private boolean foil = false;
         private boolean edible = false;
diff --git a/core/src/main/java/org/geysermc/geyser/registry/populator/CustomItemRegistryPopulator.java b/core/src/main/java/org/geysermc/geyser/registry/populator/CustomItemRegistryPopulator.java
index f2d233318..1f7bcf506 100644
--- a/core/src/main/java/org/geysermc/geyser/registry/populator/CustomItemRegistryPopulator.java
+++ b/core/src/main/java/org/geysermc/geyser/registry/populator/CustomItemRegistryPopulator.java
@@ -182,10 +182,11 @@ public class CustomItemRegistryPopulator {
         int protectionValue = 0;
         if (mapping.getArmorType() != null) {
             armorType = mapping.getArmorType();
-            protectionValue = mapping.getProtectionValue();
+            protectionValue = customItemData.protectionValue() == -1 ? mapping.getProtectionValue() : customItemData.protectionValue();
         } else if (customItemData.armorType() != null) {
             armorType = customItemData.armorType();
-            protectionValue = customItemData.protectionValue();
+            // Using 0 as fallback here because the Java item doesn't have an armor type - so its protection value would be 0
+            protectionValue = customItemData.protectionValue() == -1 ? 0 : customItemData.protectionValue();
         }
 
         if (armorType != null) {
@@ -244,13 +245,13 @@ public class CustomItemRegistryPopulator {
 
         boolean canDestroyInCreative = true;
         if (customItemData.toolType() != null) { // This is not using the isTool boolean because it is not just a render type here.
-            canDestroyInCreative = computeToolProperties(Objects.requireNonNull(customItemData.toolType()), itemProperties, componentBuilder, customItemData.attackDamage());
+            canDestroyInCreative = computeToolProperties(Objects.requireNonNull(customItemData.toolType()), itemProperties, componentBuilder, Math.max(0, customItemData.attackDamage()));
         }
         itemProperties.putBoolean("can_destroy_in_creative", canDestroyInCreative);
 
         String armorType = customItemData.armorType();
         if (armorType != null) {
-            computeArmorProperties(armorType, customItemData.protectionValue(), itemProperties, componentBuilder);
+            computeArmorProperties(armorType, Math.max(0, customItemData.protectionValue()), itemProperties, componentBuilder);
         }
 
         if (customItemData.isEdible()) {