diff --git a/src/client/InputHandler.ts b/src/client/InputHandler.ts
index c589862e4..8b38f6e40 100644
--- a/src/client/InputHandler.ts
+++ b/src/client/InputHandler.ts
@@ -1,5 +1,7 @@
 import { EventBus, GameEvent } from "../core/EventBus";
 import { UserSettings } from "../core/game/UserSettings";
+import { Game } from "../core/game/Game";
+import { UnitView } from "../core/game/GameView";
 
 export class MouseUpEvent implements GameEvent {
   constructor(
@@ -8,6 +10,16 @@ export class MouseUpEvent implements GameEvent {
   ) {}
 }
 
+/**
+ * Event emitted when a unit is selected or deselected
+ */
+export class UnitSelectionEvent implements GameEvent {
+  constructor(
+    public readonly unit: UnitView | null,
+    public readonly isSelected: boolean,
+  ) {}
+}
+
 export class MouseDownEvent implements GameEvent {
   constructor(
     public readonly x: number,
diff --git a/src/client/graphics/GameRenderer.ts b/src/client/graphics/GameRenderer.ts
index a0c34bb01..e9263f095 100644
--- a/src/client/graphics/GameRenderer.ts
+++ b/src/client/graphics/GameRenderer.ts
@@ -14,6 +14,7 @@ import { ControlPanel } from "./layers/ControlPanel";
 import { UIState } from "./UIState";
 import { BuildMenu } from "./layers/BuildMenu";
 import { UnitLayer } from "./layers/UnitLayer";
+import { UILayer } from "./layers/UILayer";
 import { StructureLayer } from "./layers/StructureLayer";
 import { PlayerInfoOverlay } from "./layers/PlayerInfoOverlay";
 import { consolex } from "../../core/Consolex";
@@ -117,7 +118,8 @@ export function createRenderer(
     new TerrainLayer(game),
     new TerritoryLayer(game, eventBus),
     new StructureLayer(game, eventBus),
-    new UnitLayer(game, eventBus, clientID),
+    new UnitLayer(game, eventBus, clientID, transformHandler),
+    new UILayer(game, eventBus, clientID, transformHandler),
     new NameLayer(game, transformHandler, clientID),
     eventsDisplay,
     buildMenu,
diff --git a/src/client/graphics/layers/UILayer.ts b/src/client/graphics/layers/UILayer.ts
new file mode 100644
index 000000000..b743f7687
--- /dev/null
+++ b/src/client/graphics/layers/UILayer.ts
@@ -0,0 +1,207 @@
+import { Colord } from "colord";
+import { Theme } from "../../../core/configuration/Config";
+import { UnitType } from "../../../core/game/Game";
+import { Layer } from "./Layer";
+import { EventBus } from "../../../core/EventBus";
+import { ClientID } from "../../../core/Schemas";
+import { GameView, UnitView } from "../../../core/game/GameView";
+import { UnitSelectionEvent } from "../../InputHandler";
+import { TransformHandler } from "../TransformHandler";
+
+/**
+ * Layer responsible for drawing UI elements that overlay the game
+ * such as selection boxes, health bars, etc.
+ */
+export class UILayer implements Layer {
+  private canvas: HTMLCanvasElement;
+  private context: CanvasRenderingContext2D;
+
+  private theme: Theme = null;
+  private selectionAnimTime = 0;
+
+  // Keep track of currently selected unit
+  private selectedUnit: UnitView | null = null;
+
+  // Keep track of previous selection box position for cleanup
+  private lastSelectionBoxCenter: {
+    x: number;
+    y: number;
+    size: number;
+  } | null = null;
+
+  // Visual settings for selection
+  private readonly SELECTION_BOX_SIZE = 6; // Size of the selection box (should be larger than the warship)
+
+  constructor(
+    private game: GameView,
+    private eventBus: EventBus,
+    private clientID: ClientID,
+    private transformHandler: TransformHandler,
+  ) {
+    this.theme = game.config().theme();
+  }
+
+  shouldTransform(): boolean {
+    return true;
+  }
+
+  tick() {
+    // Update the selection animation time
+    this.selectionAnimTime = (this.selectionAnimTime + 1) % 60;
+
+    // If there's a selected warship, redraw to update the selection box animation
+    if (this.selectedUnit && this.selectedUnit.type() === UnitType.Warship) {
+      this.drawSelectionBox(this.selectedUnit);
+    }
+  }
+
+  init() {
+    this.eventBus.on(UnitSelectionEvent, (e) => this.onUnitSelection(e));
+    this.redraw();
+  }
+
+  renderLayer(context: CanvasRenderingContext2D) {
+    context.drawImage(
+      this.canvas,
+      -this.game.width() / 2,
+      -this.game.height() / 2,
+      this.game.width(),
+      this.game.height(),
+    );
+  }
+
+  redraw() {
+    this.canvas = document.createElement("canvas");
+    this.context = this.canvas.getContext("2d");
+
+    this.canvas.width = this.game.width();
+    this.canvas.height = this.game.height();
+  }
+
+  /**
+   * Handle the unit selection event
+   */
+  private onUnitSelection(event: UnitSelectionEvent) {
+    if (event.isSelected) {
+      this.selectedUnit = event.unit;
+      if (event.unit && event.unit.type() === UnitType.Warship) {
+        this.drawSelectionBox(event.unit);
+      }
+    } else {
+      if (this.selectedUnit === event.unit) {
+        // Clear the selection box
+        if (this.lastSelectionBoxCenter) {
+          const { x, y, size } = this.lastSelectionBoxCenter;
+          this.clearSelectionBox(x, y, size);
+          this.lastSelectionBoxCenter = null;
+        }
+        this.selectedUnit = null;
+      }
+    }
+  }
+
+  /**
+   * Clear the selection box at a specific position
+   */
+  private clearSelectionBox(x: number, y: number, size: number) {
+    for (let px = x - size; px <= x + size; px++) {
+      for (let py = y - size; py <= y + size; py++) {
+        if (
+          px === x - size ||
+          px === x + size ||
+          py === y - size ||
+          py === y + size
+        ) {
+          this.clearCell(px, py);
+        }
+      }
+    }
+  }
+
+  /**
+   * Draw a selection box around the given unit
+   */
+  public drawSelectionBox(unit: UnitView) {
+    if (!unit || !unit.isActive()) {
+      return;
+    }
+
+    // Use the configured selection box size
+    const selectionSize = this.SELECTION_BOX_SIZE;
+
+    // Calculate pulsating effect based on animation time (25% variation in opacity)
+    const baseOpacity = 200;
+    const pulseAmount = 55;
+    const opacity =
+      baseOpacity + Math.sin(this.selectionAnimTime * 0.1) * pulseAmount;
+
+    // Get the unit's owner color for the box
+    const ownerColor = this.theme.territoryColor(unit.owner().info());
+
+    // Create a brighter version of the owner color for the selection
+    const selectionColor = ownerColor.lighten(0.2);
+
+    // Get current center position
+    const center = unit.tile();
+    const centerX = this.game.x(center);
+    const centerY = this.game.y(center);
+
+    // Clear previous selection box if it exists and is different from current position
+    if (
+      this.lastSelectionBoxCenter &&
+      (this.lastSelectionBoxCenter.x !== centerX ||
+        this.lastSelectionBoxCenter.y !== centerY)
+    ) {
+      const lastSize = this.lastSelectionBoxCenter.size;
+      const lastX = this.lastSelectionBoxCenter.x;
+      const lastY = this.lastSelectionBoxCenter.y;
+
+      // Clear the previous selection box
+      this.clearSelectionBox(lastX, lastY, lastSize);
+    }
+
+    // Draw the selection box
+    for (let x = centerX - selectionSize; x <= centerX + selectionSize; x++) {
+      for (let y = centerY - selectionSize; y <= centerY + selectionSize; y++) {
+        // Only draw if it's on the border (not inside or outside the box)
+        if (
+          x === centerX - selectionSize ||
+          x === centerX + selectionSize ||
+          y === centerY - selectionSize ||
+          y === centerY + selectionSize
+        ) {
+          // Create a dashed effect by only drawing some pixels
+          const dashPattern = (x + y) % 2 === 0;
+          if (dashPattern) {
+            this.paintCell(x, y, selectionColor, opacity);
+          }
+        }
+      }
+    }
+
+    // Store current selection box position for next cleanup
+    this.lastSelectionBoxCenter = {
+      x: centerX,
+      y: centerY,
+      size: selectionSize,
+    };
+  }
+
+  /**
+   * Draw health bar for a unit (placeholder for future implementation)
+   */
+  public drawHealthBar(unit: UnitView) {
+    // This is a placeholder for future health bar implementation
+    // It would draw a health bar above units that have health
+  }
+
+  paintCell(x: number, y: number, color: Colord, alpha: number) {
+    this.clearCell(x, y);
+    this.context.fillStyle = color.alpha(alpha / 255).toRgbString();
+    this.context.fillRect(x, y, 1, 1);
+  }
+
+  clearCell(x: number, y: number) {
+    this.context.clearRect(x, y, 1, 1);
+  }
+}
diff --git a/src/client/graphics/layers/UnitLayer.ts b/src/client/graphics/layers/UnitLayer.ts
index 5c900fdce..5cae90c36 100644
--- a/src/client/graphics/layers/UnitLayer.ts
+++ b/src/client/graphics/layers/UnitLayer.ts
@@ -3,7 +3,11 @@ import { Theme } from "../../../core/configuration/Config";
 import { Unit, UnitType, Player } from "../../../core/game/Game";
 import { Layer } from "./Layer";
 import { EventBus } from "../../../core/EventBus";
-import { AlternateViewEvent } from "../../InputHandler";
+import {
+  AlternateViewEvent,
+  MouseUpEvent,
+  UnitSelectionEvent,
+} from "../../InputHandler";
 import { ClientID } from "../../../core/Schemas";
 import { GameView, PlayerView, UnitView } from "../../../core/game/GameView";
 import {
@@ -12,6 +16,7 @@ import {
   TileRef,
 } from "../../../core/game/GameMap";
 import { GameUpdateType } from "../../../core/game/GameUpdates";
+import { TransformHandler } from "../TransformHandler";
 
 enum Relationship {
   Self,
@@ -33,12 +38,22 @@ export class UnitLayer implements Layer {
 
   private oldShellTile = new Map<UnitView, TileRef>();
 
+  private transformHandler: TransformHandler;
+
+  // Selected unit property as suggested in the review comment
+  private selectedUnit: UnitView | null = null;
+
+  // Configuration for unit selection
+  private readonly WARSHIP_SELECTION_RADIUS = 3; // Radius in game cells for warship selection hit zone
+
   constructor(
     private game: GameView,
     private eventBus: EventBus,
     private clientID: ClientID,
+    transformHandler: TransformHandler,
   ) {
     this.theme = game.config().theme();
+    this.transformHandler = transformHandler;
   }
 
   shouldTransform(): boolean {
@@ -56,9 +71,89 @@ export class UnitLayer implements Layer {
 
   init() {
     this.eventBus.on(AlternateViewEvent, (e) => this.onAlternativeViewEvent(e));
+    this.eventBus.on(MouseUpEvent, (e) => this.onMouseUp(e));
+    this.eventBus.on(UnitSelectionEvent, (e) => this.onUnitSelectionChange(e));
     this.redraw();
   }
 
+  /**
+   * Find player-owned warships near the given cell within a configurable radius
+   * @param cell The cell to check
+   * @returns Array of player's warships in range, sorted by distance (closest first)
+   */
+  private findWarshipsNearCell(cell: { x: number; y: number }): UnitView[] {
+    const clickRef = this.game.ref(cell.x, cell.y);
+
+    // Make sure we have the current player
+    if (this.myPlayer == null) {
+      this.myPlayer = this.game.playerByClientID(this.clientID);
+    }
+
+    // Only select warships owned by the player
+    return this.game
+      .units(UnitType.Warship)
+      .filter(
+        (unit) =>
+          unit.isActive() &&
+          unit.owner() === this.myPlayer && // Only allow selecting own warships
+          this.game.manhattanDist(unit.tile(), clickRef) <=
+            this.WARSHIP_SELECTION_RADIUS,
+      )
+      .sort((a, b) => {
+        // Sort by distance (closest first)
+        const distA = this.game.manhattanDist(a.tile(), clickRef);
+        const distB = this.game.manhattanDist(b.tile(), clickRef);
+        return distA - distB;
+      });
+  }
+
+  private onMouseUp(event: MouseUpEvent) {
+    // Convert screen coordinates to world coordinates
+    const cell = this.transformHandler.screenToWorldCoordinates(
+      event.x,
+      event.y,
+    );
+
+    // Find warships near this cell, sorted by distance
+    const nearbyWarships = this.findWarshipsNearCell(cell);
+
+    if (nearbyWarships.length > 0) {
+      // Toggle selection of the closest warship
+      const clickedUnit = nearbyWarships[0];
+      if (this.selectedUnit === clickedUnit) {
+        // Deselect if already selected
+        this.eventBus.emit(new UnitSelectionEvent(clickedUnit, false));
+      } else {
+        // Select the new unit
+        this.eventBus.emit(new UnitSelectionEvent(clickedUnit, true));
+      }
+    } else if (this.selectedUnit) {
+      // If clicked elsewhere and there's a selection, deselect it
+      this.eventBus.emit(new UnitSelectionEvent(this.selectedUnit, false));
+    }
+  }
+
+  /**
+   * Handle unit selection changes
+   */
+  private onUnitSelectionChange(event: UnitSelectionEvent) {
+    if (event.isSelected) {
+      this.selectedUnit = event.unit;
+    } else if (this.selectedUnit === event.unit) {
+      this.selectedUnit = null;
+    }
+  }
+
+  /**
+   * Handle unit deactivation or destruction
+   * If the selected unit is removed from the game, deselect it
+   */
+  private handleUnitDeactivation(unit: UnitView) {
+    if (this.selectedUnit === unit && !unit.isActive()) {
+      this.eventBus.emit(new UnitSelectionEvent(unit, false));
+    }
+  }
+
   renderLayer(context: CanvasRenderingContext2D) {
     context.drawImage(
       this.canvas,
@@ -101,6 +196,11 @@ export class UnitLayer implements Layer {
   }
 
   onUnitEvent(unit: UnitView) {
+    // Check if unit was deactivated
+    if (!unit.isActive()) {
+      this.handleUnitDeactivation(unit);
+    }
+
     switch (unit.type()) {
       case UnitType.TransportShip:
         this.handleBoatEvent(unit);