diff --git a/src/landscape.cpp b/src/landscape.cpp
index 9065844904..d9bc4bc659 100644
--- a/src/landscape.cpp
+++ b/src/landscape.cpp
@@ -1223,13 +1223,13 @@ static void River_GetNeighbours(AyStar *aystar, PathNode *current)
 {
 	TileIndex tile = current->GetTile();
 
-	aystar->num_neighbours = 0;
+	aystar->neighbours.clear();
 	for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
 		TileIndex t2 = tile + TileOffsByDiagDir(d);
 		if (IsValidTile(t2) && FlowsDown(tile, t2)) {
-			aystar->neighbours[aystar->num_neighbours].m_tile = t2;
-			aystar->neighbours[aystar->num_neighbours].m_td = INVALID_TRACKDIR;
-			aystar->num_neighbours++;
+			auto &neighbour = aystar->neighbours.emplace_back();
+			neighbour.m_tile = t2;
+			neighbour.m_td = INVALID_TRACKDIR;
 		}
 	}
 }
diff --git a/src/pathfinder/aystar.cpp b/src/pathfinder/aystar.cpp
index 711f7c0467..41ffc84668 100644
--- a/src/pathfinder/aystar.cpp
+++ b/src/pathfinder/aystar.cpp
@@ -111,9 +111,9 @@ int AyStar::Loop()
 	this->GetNeighbours(this, current);
 
 	/* Go through all neighbours */
-	for (int i = 0; i < this->num_neighbours; i++) {
+	for (auto &neighbour : this->neighbours) {
 		/* Check and add them to the OpenList if needed */
-		this->CheckTile(&this->neighbours[i], current);
+		this->CheckTile(&neighbour, current);
 	}
 
 	if (this->max_search_nodes != 0 && this->nodes.ClosedCount() >= this->max_search_nodes) {
diff --git a/src/pathfinder/aystar.h b/src/pathfinder/aystar.h
index d375a052a5..8fa8490644 100644
--- a/src/pathfinder/aystar.h
+++ b/src/pathfinder/aystar.h
@@ -125,10 +125,8 @@ struct AyStar {
 	int max_path_cost;    ///< If the g-value goes over this number, it stops searching, 0 = infinite.
 	int max_search_nodes = AYSTAR_DEF_MAX_SEARCH_NODES; ///< The maximum number of nodes that will be expanded, 0 = infinite.
 
-	/* These should be filled with the neighbours of a tile by
-	 * GetNeighbours */
-	AyStarNode neighbours[12];
-	uint8_t num_neighbours;
+	/* These should be filled with the neighbours of a tile by GetNeighbours */
+	std::vector<AyStarNode> neighbours;
 
 	/* These will contain the methods for manipulating the AyStar. Only
 	 * Main() should be called externally */