diff --git a/paper-api/src/main/java/io/papermc/paper/event/entity/PufferFishStateChangeEvent.java b/paper-api/src/main/java/io/papermc/paper/event/entity/PufferFishStateChangeEvent.java
new file mode 100644
index 0000000000..b4521d64ee
--- /dev/null
+++ b/paper-api/src/main/java/io/papermc/paper/event/entity/PufferFishStateChangeEvent.java
@@ -0,0 +1,85 @@
+package io.papermc.paper.event.entity;
+
+import org.bukkit.entity.PufferFish;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Called just before a {@link PufferFish} inflates or deflates.
+ */
+@NullMarked
+public class PufferFishStateChangeEvent extends EntityEvent implements Cancellable {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final int newPuffState;
+    private boolean cancelled;
+
+    @ApiStatus.Internal
+    public PufferFishStateChangeEvent(final PufferFish entity, final int newPuffState) {
+        super(entity);
+        this.newPuffState = newPuffState;
+    }
+
+    @Override
+    public PufferFish getEntity() {
+        return (PufferFish) super.getEntity();
+    }
+
+    /**
+     * Get the <strong>new</strong> puff state of the {@link PufferFish}.
+     * <p>
+     * This is what the {@link PufferFish}'s new puff state will be after this event if it isn't cancelled.<br>
+     * Refer to {@link PufferFish#getPuffState()} to get the current puff state.
+     *
+     * @return The <strong>new</strong> puff state, 0 being not inflated, 1 being slightly inflated and 2 being fully inflated
+     */
+    public int getNewPuffState() {
+        return this.newPuffState;
+    }
+
+    /**
+     * Get if the {@link PufferFish} is going to inflate.
+     *
+     * @return If it's going to inflate
+     */
+    public boolean isInflating() {
+        return this.newPuffState > this.getEntity().getPuffState();
+    }
+
+    /**
+     * Get if the {@link PufferFish} is going to deflate.
+     *
+     * @return If it's going to deflate
+     */
+    public boolean isDeflating() {
+        return this.newPuffState < this.getEntity().getPuffState();
+    }
+
+    /**
+     * Set whether to cancel the {@link PufferFish} (in/de)flating.
+     *
+     * @param cancel {@code true} if you wish to cancel the (in/de)flation
+     */
+    @Override
+    public void setCancelled(final boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}