diff --git a/src/puya/awst/function_traverser.py b/src/puya/awst/function_traverser.py
index 25f83ae8f4..5a8c9f571c 100644
--- a/src/puya/awst/function_traverser.py
+++ b/src/puya/awst/function_traverser.py
@@ -244,11 +244,6 @@ def visit_bytes_unary_operation(self, expr: awst_nodes.BytesUnaryOperation) -> N
     def visit_not_expression(self, expr: awst_nodes.Not) -> None:
         expr.expr.accept(self)
 
-    @typing.override
-    def visit_contains_expression(self, expr: awst_nodes.Contains) -> None:
-        expr.item.accept(self)
-        expr.sequence.accept(self)
-
     @typing.override
     def visit_block(self, statement: awst_nodes.Block) -> None:
         for stmt in statement.body:
diff --git a/src/puya/awst/nodes.py b/src/puya/awst/nodes.py
index 6dc95475d0..be944136db 100644
--- a/src/puya/awst/nodes.py
+++ b/src/puya/awst/nodes.py
@@ -1255,41 +1255,6 @@ def accept(self, visitor: ExpressionVisitor[T]) -> T:
         return visitor.visit_not_expression(self)
 
 
-@attrs.frozen
-class Contains(Expression):
-    item: Expression
-    sequence: Expression
-    wtype: WType = attrs.field(default=wtypes.bool_wtype, init=False)
-
-    def __attrs_post_init__(self) -> None:
-        if self.sequence.wtype == wtypes.bytes_wtype:
-            raise InternalError(
-                "Use IsSubstring for 'in' or 'not in' checks with Bytes", self.source_location
-            )
-        # TODO: this type handling here probably isn't scalable
-        if isinstance(self.sequence.wtype, wtypes.WArray):
-            if self.sequence.wtype.element_type != self.item.wtype:
-                raise CodeError(
-                    f"array element type {self.sequence.wtype.element_type}"
-                    f" differs from {self.item.wtype}",
-                    self.source_location,
-                )
-        elif isinstance(self.sequence.wtype, wtypes.WTuple):
-            if self.item.wtype not in self.sequence.wtype.types:
-                raise CodeError(
-                    f"{self.sequence.wtype} does not have element with type {self.item.wtype}",
-                    self.source_location,
-                )
-        else:
-            raise CodeError(
-                f"Type doesn't support in/not in checks: {self.sequence.wtype}",
-                self.source_location,
-            )
-
-    def accept(self, visitor: ExpressionVisitor[T]) -> T:
-        return visitor.visit_contains_expression(self)
-
-
 @attrs.frozen
 class UInt64AugmentedAssignment(Statement):
     target: Lvalue = attrs.field(validator=[wtype_is_uint64])
diff --git a/src/puya/awst/to_code_visitor.py b/src/puya/awst/to_code_visitor.py
index 923144fc07..ff2162f0a4 100644
--- a/src/puya/awst/to_code_visitor.py
+++ b/src/puya/awst/to_code_visitor.py
@@ -60,9 +60,6 @@ def visit_arc4_decode(self, expr: nodes.ARC4Decode) -> str:
     def visit_arc4_encode(self, expr: nodes.ARC4Encode) -> str:
         return f"arc4_encode({expr.value.accept(self)}, {expr.wtype})"
 
-    def visit_contains_expression(self, expr: nodes.Contains) -> str:
-        return f"{expr.item.accept(self)} IS IN {expr.sequence.accept(self)}"
-
     def visit_reinterpret_cast(self, expr: nodes.ReinterpretCast) -> str:
         return f"reinterpret_cast<{expr.wtype}>({expr.expr.accept(self)})"
 
diff --git a/src/puya/awst/visitors.py b/src/puya/awst/visitors.py
index 8aed9996d3..df963ba259 100644
--- a/src/puya/awst/visitors.py
+++ b/src/puya/awst/visitors.py
@@ -226,9 +226,6 @@ def visit_bytes_unary_operation(self, expr: puya.awst.nodes.BytesUnaryOperation)
     @abstractmethod
     def visit_not_expression(self, expr: puya.awst.nodes.Not) -> T: ...
 
-    @abstractmethod
-    def visit_contains_expression(self, expr: puya.awst.nodes.Contains) -> T: ...
-
     @abstractmethod
     def visit_reinterpret_cast(self, expr: puya.awst.nodes.ReinterpretCast) -> T: ...
 
diff --git a/src/puya/ir/builder/main.py b/src/puya/ir/builder/main.py
index 0205f1d018..97c2c1107f 100644
--- a/src/puya/ir/builder/main.py
+++ b/src/puya/ir/builder/main.py
@@ -833,54 +833,6 @@ def visit_not_expression(self, expr: awst_nodes.Not) -> TExpression:
             source_location=expr.source_location,
         )
 
-    def visit_contains_expression(self, expr: awst_nodes.Contains) -> TExpression:
-        item_register = self.visit_and_materialise_single(expr.item)
-
-        if not isinstance(expr.sequence.wtype, wtypes.WTuple):
-            raise InternalError(
-                f"Containment operation IR lowering"
-                f" not implemented for sequence type {expr.sequence.wtype.name}",
-                expr.source_location,
-            )
-        items_sequence = [
-            item
-            for item, item_wtype in zip(
-                self.visit_and_materialise(expr.sequence), expr.sequence.wtype.types, strict=True
-            )
-            if item_wtype == expr.item.wtype
-        ]
-
-        condition = None
-        for item in items_sequence:
-            equal_i = Intrinsic(
-                op=get_comparison_op_for_wtype(awst_nodes.NumericComparison.eq, expr.item.wtype),
-                args=[
-                    item_register,
-                    item,
-                ],
-                source_location=expr.source_location,
-            )
-            if not condition:
-                condition = equal_i
-                continue
-            left_var = assign_temp(
-                self.context,
-                source=condition,
-                temp_description="contains",
-                source_location=expr.source_location,
-            )
-            right_var = assign_temp(
-                self.context,
-                source=equal_i,
-                temp_description="is_equal",
-                source_location=expr.source_location,
-            )
-            condition = Intrinsic(
-                op=AVMOp.or_, args=[left_var, right_var], source_location=expr.source_location
-            )
-
-        return condition or UInt64Constant(source_location=expr.source_location, value=0)
-
     def visit_reinterpret_cast(self, expr: awst_nodes.ReinterpretCast) -> TExpression:
         # should be a no-op for us, but we validate the cast here too
         source = self.visit_expr(expr.expr)