diff --git a/core/src/main.jl b/core/src/main.jl
index f8b1ee004..8fedf50bf 100644
--- a/core/src/main.jl
+++ b/core/src/main.jl
@@ -14,6 +14,9 @@ function run(config::Config)::Model
     return model
 end
 
+main(ARGS::Vector{String})::Cint = main(only(ARGS))
+main()::Cint = main(ARGS)
+
 """
     main(toml_path::AbstractString)::Cint
     main(ARGS::Vector{String})::Cint
diff --git a/core/src/model.jl b/core/src/model.jl
index 175c7ee47..11f2059ed 100644
--- a/core/src/model.jl
+++ b/core/src/model.jl
@@ -51,6 +51,9 @@ function Model(config::Config)::Model
     # so we can directly close it again.
     db = SQLite.DB(db_path)
 
+    if !valid_nodes(db)
+        error("Invalid nodes found.")
+    end
     if !valid_edge_types(db)
         error("Invalid edge types found.")
     end
@@ -101,13 +104,6 @@ function Model(config::Config)::Model
         state = load_structvector(db, config, BasinStateV1)
         n = length(get_ids(db, "Basin"))
 
-        sql = "SELECT node_id FROM Node ORDER BY node_id"
-        node_id = only(execute(columntable, db, sql))
-        if !allunique(node_id)
-            error(
-                "Node IDs need to be globally unique until https://github.com/Deltares/Ribasim/issues/1262 is fixed.",
-            )
-        end
     finally
         # always close the database, also in case of an error
         close(db)
diff --git a/core/src/validation.jl b/core/src/validation.jl
index 85c0050d0..5c3d08276 100644
--- a/core/src/validation.jl
+++ b/core/src/validation.jl
@@ -162,6 +162,21 @@ function valid_config(config::Config)::Bool
     return !errors
 end
 
+function valid_nodes(db::DB)::Bool
+    errors = false
+
+    sql = "SELECT node_type, node_id FROM Node GROUP BY node_type, node_id HAVING COUNT(*) > 1"
+    node_type, node_id = execute(columntable, db, sql)
+
+    for (node_type, node_id) in zip(node_type, node_id)
+        errors = true
+        id = NodeID(node_type, node_id)
+        @error "Multiple occurrences of node $id found in Node table."
+    end
+
+    return !errors
+end
+
 """
 Test for each node given its node type whether the nodes that
 # are downstream ('down-edge') of this node are of an allowed type
diff --git a/core/test/run_models_test.jl b/core/test/run_models_test.jl
index 45fa53f73..b1a570a4a 100644
--- a/core/test/run_models_test.jl
+++ b/core/test/run_models_test.jl
@@ -128,8 +128,8 @@
     @testset "Results values" begin
         @test flow.time[1] == DateTime(2020)
         @test coalesce.(flow.edge_id[1:2], -1) == [0, 1]
-        @test flow.from_node_id[1:2] == [6, 0]
-        @test flow.to_node_id[1:2] == [0, 922]
+        @test flow.from_node_id[1:2] == [6, 6]
+        @test flow.to_node_id[1:2] == [6, 2147483647]
 
         @test basin.storage[1] ≈ 1.0
         @test basin.level[1] ≈ 0.044711584
diff --git a/coupling/delwaq/generate.py b/coupling/delwaq/generate.py
index df4ce90f6..583c26458 100644
--- a/coupling/delwaq/generate.py
+++ b/coupling/delwaq/generate.py
@@ -44,7 +44,7 @@ def generate(toml_path: Path) -> tuple[nx.DiGraph, set[str]]:
     for row in model.node_table().df.itertuples():
         if row.node_type not in ribasim.geometry.edge.SPATIALCONTROLNODETYPES:
             G.add_node(
-                row.node_id,
+                row.node_type + str(row.node_id),
                 type=row.node_type,
                 id=row.node_id,
                 x=row.geometry.x,
@@ -53,7 +53,12 @@ def generate(toml_path: Path) -> tuple[nx.DiGraph, set[str]]:
             )
     for row in model.edge.df.itertuples():
         if row.edge_type == "flow":
-            G.add_edge(row.from_node_id, row.to_node_id, id=[row.Index], duplicate=None)
+            G.add_edge(
+                row.from_node_type + str(row.from_node_id),
+                row.to_node_type + str(row.to_node_id),
+                id=[row.Index],
+                duplicate=None,
+            )
 
     # Simplify network, only keeping Basins and Boundaries.
     # We find an unwanted node, remove it,
diff --git a/python/ribasim/ribasim/model.py b/python/ribasim/ribasim/model.py
index 6c01525d7..b214ddd3f 100644
--- a/python/ribasim/ribasim/model.py
+++ b/python/ribasim/ribasim/model.py
@@ -52,7 +52,6 @@
     MissingOptionalModule,
     _edge_lookup,
     _node_lookup,
-    _node_lookup_numpy,
     _time_in_ns,
 )
 
@@ -174,16 +173,7 @@ def _save(self, directory: DirectoryPath, input_dir: DirectoryPath):
         db_path.unlink(missing_ok=True)
         context_file_loading.get()["database"] = db_path
         self.edge._save(directory, input_dir)
-
         node = self.node_table()
-        assert node.df is not None
-        # Temporarily require unique node_id for #1262
-        # and copy them to the fid for #1306.
-        if not node.df["node_id"].is_unique:
-            raise ValueError("node_id must be unique")
-        node.df.set_index("node_id", drop=False, inplace=True)
-        node.df.index.name = "fid"
-        node.df.sort_index(inplace=True)
         node._save(directory, input_dir)
 
         for sub in self._nodes():
@@ -209,7 +199,7 @@ def _apply_crs_function(self, function_name: str, crs: str) -> None:
         self.crs = crs
 
     def node_table(self) -> NodeTable:
-        """Compute the full NodeTable from all node types."""
+        """Compute the full sorted NodeTable from all node types."""
         df_chunks = [node.node.df.set_crs(self.crs) for node in self._nodes()]  # type:ignore
         df = pd.concat(df_chunks, ignore_index=True)
         node_table = NodeTable(df=df)
@@ -402,12 +392,6 @@ def to_xugrid(self, add_flow: bool = False, add_allocation: bool = False):
         node_df = self.node_table().df
         assert node_df is not None
 
-        # This will need to be adopted for locally unique node IDs,
-        # otherwise the `node_lookup` with `argsort` is not correct.
-        if not node_df.node_id.is_unique:
-            raise ValueError("node_id must be unique")
-        node_df.sort_values("node_id", inplace=True)
-
         assert self.edge.df is not None
         edge_df = self.edge.df.copy()
         # We assume only the flow network is of interest.
@@ -417,7 +401,13 @@ def to_xugrid(self, add_flow: bool = False, add_allocation: bool = False):
         edge_id = edge_df.index.to_numpy()
         from_node_id = edge_df.from_node_id.to_numpy()
         to_node_id = edge_df.to_node_id.to_numpy()
-        node_lookup = _node_lookup_numpy(node_id)
+        node_lookup = _node_lookup(node_df)
+        from_node_index = pd.MultiIndex.from_frame(
+            edge_df[["from_node_type", "from_node_id"]]
+        )
+        to_node_index = pd.MultiIndex.from_frame(
+            edge_df[["to_node_type", "to_node_id"]]
+        )
 
         grid = xugrid.Ugrid1d(
             node_x=node_df.geometry.x,
@@ -425,8 +415,8 @@ def to_xugrid(self, add_flow: bool = False, add_allocation: bool = False):
             fill_value=-1,
             edge_node_connectivity=np.column_stack(
                 (
-                    node_lookup[from_node_id],
-                    node_lookup[to_node_id],
+                    node_lookup.loc[from_node_index],
+                    node_lookup.loc[to_node_index],
                 )
             ),
             name="ribasim",
@@ -444,7 +434,7 @@ def to_xugrid(self, add_flow: bool = False, add_allocation: bool = False):
         uds = uds.assign_coords(to_node_id=(edge_dim, to_node_id))
 
         if add_flow:
-            uds = self._add_flow(uds)
+            uds = self._add_flow(uds, node_lookup)
         elif add_allocation:
             uds = self._add_allocation(uds)
 
@@ -456,7 +446,7 @@ def _checked_toml_path(self) -> Path:
             raise FileNotFoundError("Model must be written to disk to add results.")
         return toml_path
 
-    def _add_flow(self, uds):
+    def _add_flow(self, uds, node_lookup):
         toml_path = self._checked_toml_path()
 
         results_path = toml_path.parent / self.results_dir
@@ -477,17 +467,19 @@ def _add_flow(self, uds):
         # add the xugrid dimension indices to the dataframes
         edge_dim = uds.grid.edge_dimension
         node_dim = uds.grid.node_dimension
-        node_lookup = _node_lookup(uds)
         edge_lookup = _edge_lookup(uds)
         flow_df[edge_dim] = edge_lookup[flow_df["edge_id"]].to_numpy()
-        basin_df[node_dim] = node_lookup[basin_df["node_id"]].to_numpy()
+        # Use a MultiIndex to ensure the lookup results is the same length as basin_df
+        basin_df["node_type"] = "Basin"
+        multi_index = pd.MultiIndex.from_frame(basin_df[["node_type", "node_id"]])
+        basin_df[node_dim] = node_lookup.loc[multi_index].to_numpy()
 
         # add flow results to the UgridDataset
         flow_da = flow_df.set_index(["time", edge_dim])["flow_rate"].to_xarray()
         uds[flow_da.name] = flow_da
 
         # add basin results to the UgridDataset
-        basin_df.drop(columns=["node_id"], inplace=True)
+        basin_df.drop(columns=["node_type", "node_id"], inplace=True)
         basin_ds = basin_df.set_index(["time", node_dim]).to_xarray()
 
         for var_name, da in basin_ds.data_vars.items():
diff --git a/python/ribasim/ribasim/utils.py b/python/ribasim/ribasim/utils.py
index 57fa9a684..b8fd26a02 100644
--- a/python/ribasim/ribasim/utils.py
+++ b/python/ribasim/ribasim/utils.py
@@ -1,6 +1,5 @@
 import re
 
-import numpy as np
 import pandas as pd
 from pandera.dtypes import Int32
 from pandera.typing import Series
@@ -22,28 +21,14 @@ def __getattr__(self, name):
         raise ImportError(f"{self.name} is required for this functionality")
 
 
-def _node_lookup_numpy(node_id) -> Series[Int32]:
-    """Create a lookup table from from node_id to the node dimension index.
+def _node_lookup(df) -> Series[Int32]:
+    """Create a lookup table from from (node_type, node_id) to the node dimension index.
 
     Used when adding data onto the nodes of an xugrid dataset.
     """
-    return pd.Series(
-        index=node_id,
-        data=node_id.argsort().astype(np.int32),
-        name="node_index",
-    )
-
-
-def _node_lookup(uds) -> Series[Int32]:
-    """Create a lookup table from from node_id to the node dimension index.
-
-    Used when adding data onto the nodes of an xugrid dataset.
-    """
-    return pd.Series(
-        index=uds["node_id"],
-        data=uds[uds.grid.node_dimension],
-        name="node_index",
-    )
+    return df.reset_index(names="node_index").set_index(["node_type", "node_id"])[
+        "node_index"
+    ]
 
 
 def _edge_lookup(uds) -> Series[Int32]:
diff --git a/python/ribasim/tests/test_model.py b/python/ribasim/tests/test_model.py
index 433b275c0..c6c91ee06 100644
--- a/python/ribasim/tests/test_model.py
+++ b/python/ribasim/tests/test_model.py
@@ -12,6 +12,7 @@
 from ribasim.geometry.edge import NodeData
 from ribasim.input_base import esc_id
 from ribasim.model import Model
+from ribasim_testmodels import basic_model, trivial_model
 from shapely import Point
 
 
@@ -221,8 +222,9 @@ def test_indexing(basic):
         model.basin.time[1]
 
 
-def test_xugrid(basic, tmp_path):
-    uds = basic.to_xugrid(add_flow=False)
+@pytest.mark.parametrize("model", [basic_model(), trivial_model()])
+def test_xugrid(model, tmp_path):
+    uds = model.to_xugrid(add_flow=False)
     assert isinstance(uds, xugrid.UgridDataset)
     assert uds.grid.edge_dimension == "ribasim_nEdges"
     assert uds.grid.node_dimension == "ribasim_nNodes"
@@ -233,15 +235,15 @@ def test_xugrid(basic, tmp_path):
     assert uds.attrs["Conventions"] == "CF-1.9 UGRID-1.0"
 
     with pytest.raises(FileNotFoundError, match="Model must be written to disk"):
-        basic.to_xugrid(add_flow=True)
+        model.to_xugrid(add_flow=True)
 
-    basic.write(tmp_path / "ribasim.toml")
+    model.write(tmp_path / "ribasim.toml")
     with pytest.raises(FileNotFoundError, match="Cannot find results"):
-        basic.to_xugrid(add_flow=True)
+        model.to_xugrid(add_flow=True)
     with pytest.raises(FileNotFoundError, match="or allocation is not used"):
-        basic.to_xugrid(add_flow=False, add_allocation=True)
+        model.to_xugrid(add_flow=False, add_allocation=True)
     with pytest.raises(ValueError, match="Cannot add both allocation and flow results"):
-        basic.to_xugrid(add_flow=True, add_allocation=True)
+        model.to_xugrid(add_flow=True, add_allocation=True)
 
 
 def test_to_crs(bucket: Model):
diff --git a/python/ribasim_testmodels/ribasim_testmodels/trivial.py b/python/ribasim_testmodels/ribasim_testmodels/trivial.py
index ad3669eb3..2864edbd3 100644
--- a/python/ribasim_testmodels/ribasim_testmodels/trivial.py
+++ b/python/ribasim_testmodels/ribasim_testmodels/trivial.py
@@ -40,20 +40,20 @@ def trivial_model() -> Model:
         ],
     )
 
-    # TODO largest signed 64 bit integer, to check encoding
-    terminal_id = 922  # 3372036854775807
+    # TODO largest signed 32 bit integer, to check encoding
+    terminal_id = 2147483647
     model.terminal.add(Node(terminal_id, Point(500, 200)))
     model.tabulated_rating_curve.add(
-        Node(0, Point(450, 200)),
+        Node(6, Point(450, 200)),
         [tabulated_rating_curve.Static(level=[0.0, 1.0], flow_rate=[0.0, 10 / 86400])],
     )
 
     model.edge.add(
         model.basin[6],
-        model.tabulated_rating_curve[0],
+        model.tabulated_rating_curve[6],
     )
     model.edge.add(
-        model.tabulated_rating_curve[0],
+        model.tabulated_rating_curve[6],
         model.terminal[terminal_id],
     )