diff --git a/http-api/src/main/java/net/runelite/http/api/worlds/WorldClient.java b/http-api/src/main/java/net/runelite/http/api/worlds/WorldClient.java
index fbdbca9ad8..f213abcfa3 100644
--- a/http-api/src/main/java/net/runelite/http/api/worlds/WorldClient.java
+++ b/http-api/src/main/java/net/runelite/http/api/worlds/WorldClient.java
@@ -61,7 +61,7 @@ public class WorldClient
 				if (!response.isSuccessful())
 				{
 					logger.debug("Error looking up worlds: {}", response);
-					return null;
+					return Observable.just(null);
 				}
 
 				InputStream in = response.body().byteStream();
@@ -69,7 +69,7 @@ public class WorldClient
 			}
 			catch (JsonParseException ex)
 			{
-				throw new IOException(ex);
+				return Observable.error(ex);
 			}
 		});
 	}
diff --git a/runelite-client/src/main/java/net/runelite/client/plugins/defaultworld/DefaultWorldPlugin.java b/runelite-client/src/main/java/net/runelite/client/plugins/defaultworld/DefaultWorldPlugin.java
index 0999eda3c1..d8aed33f04 100644
--- a/runelite-client/src/main/java/net/runelite/client/plugins/defaultworld/DefaultWorldPlugin.java
+++ b/runelite-client/src/main/java/net/runelite/client/plugins/defaultworld/DefaultWorldPlugin.java
@@ -25,6 +25,7 @@
 package net.runelite.client.plugins.defaultworld;
 
 import com.google.inject.Provides;
+import io.reactivex.schedulers.Schedulers;
 import java.io.IOException;
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -32,6 +33,7 @@ import lombok.extern.slf4j.Slf4j;
 import net.runelite.api.Client;
 import net.runelite.api.GameState;
 import net.runelite.api.events.GameStateChanged;
+import net.runelite.client.callback.ClientThread;
 import net.runelite.client.config.ConfigManager;
 import net.runelite.client.eventbus.EventBus;
 import net.runelite.client.events.SessionOpen;
@@ -60,6 +62,9 @@ public class DefaultWorldPlugin extends Plugin
 	@Inject
 	private EventBus eventBus;
 
+	@Inject
+	private ClientThread clientThread;
+
 	private final WorldClient worldClient = new WorldClient();
 	private int worldCache;
 	private boolean worldChangeRequired;
@@ -122,39 +127,39 @@ public class DefaultWorldPlugin extends Plugin
 			return;
 		}
 
-		try
-		{
-			final WorldResult worldResult = worldClient.lookupWorlds();
+		worldClient.lookupWorlds()
+			.subscribeOn(Schedulers.io())
+			.observeOn(Schedulers.from(clientThread))
+			.subscribe(
+				(worldResult) ->
+				{
+					if (worldResult == null)
+					{
+						return;
+					}
 
-			if (worldResult == null)
-			{
-				return;
-			}
+					final World world = worldResult.findWorld(correctedWorld);
 
-			final World world = worldResult.findWorld(correctedWorld);
+					if (world != null)
+					{
+						final net.runelite.api.World rsWorld = client.createWorld();
+						rsWorld.setActivity(world.getActivity());
+						rsWorld.setAddress(world.getAddress());
+						rsWorld.setId(world.getId());
+						rsWorld.setPlayerCount(world.getPlayers());
+						rsWorld.setLocation(world.getLocation());
+						rsWorld.setTypes(WorldUtil.toWorldTypes(world.getTypes()));
 
-			if (world != null)
-			{
-				final net.runelite.api.World rsWorld = client.createWorld();
-				rsWorld.setActivity(world.getActivity());
-				rsWorld.setAddress(world.getAddress());
-				rsWorld.setId(world.getId());
-				rsWorld.setPlayerCount(world.getPlayers());
-				rsWorld.setLocation(world.getLocation());
-				rsWorld.setTypes(WorldUtil.toWorldTypes(world.getTypes()));
-
-				client.changeWorld(rsWorld);
-				log.debug("Applied new world {}", correctedWorld);
-			}
-			else
-			{
-				log.warn("World {} not found.", correctedWorld);
-			}
-		}
-		catch (IOException e)
-		{
-			log.warn("Error looking up world {}. Error: {}", correctedWorld, e);
-		}
+						client.changeWorld(rsWorld);
+						log.debug("Applied new world {}", correctedWorld);
+					}
+					else
+					{
+						log.warn("World {} not found.", correctedWorld);
+					}
+				},
+				(e) -> log.warn("Error looking up world {}. Error: {}", correctedWorld, e)
+			);
 	}
 
 	private void applyWorld()
diff --git a/runelite-client/src/main/java/net/runelite/client/plugins/worldhopper/WorldHopperPlugin.java b/runelite-client/src/main/java/net/runelite/client/plugins/worldhopper/WorldHopperPlugin.java
index 7613e456ce..89838a6cff 100644
--- a/runelite-client/src/main/java/net/runelite/client/plugins/worldhopper/WorldHopperPlugin.java
+++ b/runelite-client/src/main/java/net/runelite/client/plugins/worldhopper/WorldHopperPlugin.java
@@ -29,6 +29,7 @@ import com.google.common.base.Stopwatch;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ObjectArrays;
 import com.google.inject.Provides;
+import io.reactivex.schedulers.Schedulers;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import java.time.Duration;
@@ -502,22 +503,21 @@ public class WorldHopperPlugin extends Plugin
 	{
 		log.debug("Fetching worlds");
 
-		try
-		{
-			WorldResult worldResult = new WorldClient().lookupWorlds();
-
-			if (worldResult != null)
-			{
-				worldResult.getWorlds().sort(Comparator.comparingInt(World::getId));
-				this.worldResult = worldResult;
-				this.lastFetch = Instant.now();
-				updateList();
-			}
-		}
-		catch (IOException ex)
-		{
-			log.warn("Error looking up worlds", ex);
-		}
+		new WorldClient().lookupWorlds()
+			.subscribeOn(Schedulers.io())
+			.subscribe(
+				(worldResult) ->
+				{
+					if (worldResult != null)
+					{
+						worldResult.getWorlds().sort(Comparator.comparingInt(World::getId));
+						this.worldResult = worldResult;
+						this.lastFetch = Instant.now();
+						updateList();
+					}
+				},
+				(ex) -> log.warn("Error looking up worlds", ex)
+			);
 	}
 
 	/**