diff --git a/quint/src/ir/IRTransformer.ts b/quint/src/ir/IRTransformer.ts
index 3f3eb6963..5cf1389c1 100644
--- a/quint/src/ir/IRTransformer.ts
+++ b/quint/src/ir/IRTransformer.ts
@@ -483,6 +483,9 @@ function transformExpression(transformer: IRTransformer, expr: ir.QuintEx): ir.Q
         newExpr = transformer.enterLambda(newExpr)
       }
 
+      newExpr.params = newExpr.params.map(p =>
+        p.typeAnnotation ? { ...p, typeAnnotation: transformType(transformer, p.typeAnnotation) } : p
+      )
       newExpr.expr = transformExpression(transformer, newExpr.expr)
 
       if (transformer.exitLambda) {
diff --git a/quint/src/ir/IRVisitor.ts b/quint/src/ir/IRVisitor.ts
index 282f048ec..879eb112b 100644
--- a/quint/src/ir/IRVisitor.ts
+++ b/quint/src/ir/IRVisitor.ts
@@ -456,7 +456,11 @@ export function walkExpression(visitor: IRVisitor, expr: ir.QuintEx): void {
       if (visitor.enterLambda) {
         visitor.enterLambda(expr)
       }
-
+      expr.params.forEach(p => {
+        if (p.typeAnnotation) {
+          walkType(visitor, p.typeAnnotation)
+        }
+      })
       walkExpression(visitor, expr.expr)
 
       if (visitor.exitLambda) {
diff --git a/quint/test/ir/IRTransformer.test.ts b/quint/test/ir/IRTransformer.test.ts
index c01ce0d51..70b210cbc 100644
--- a/quint/test/ir/IRTransformer.test.ts
+++ b/quint/test/ir/IRTransformer.test.ts
@@ -41,6 +41,26 @@ describe('enterExpr', () => {
 
     assert.deepEqual(moduleToString(result), moduleToString(expectedModule))
   })
+
+  it('transforms paramater type annotations', () => {
+    class TestTransformer implements IRTransformer {
+      exitType(_: QuintType): QuintType {
+        return { kind: 'var', name: 'trans' }
+      }
+    }
+
+    const transformer = new TestTransformer()
+
+    const m = buildModuleWithDecls(['def foo(x: int, b: int, c: str): int = 42'])
+
+    const transformedDecl = transformModule(transformer, m).declarations[0]
+    assert(transformedDecl.kind === 'def')
+    assert(transformedDecl.expr.kind === 'lambda')
+    transformedDecl.expr.params.forEach(p => {
+      assert(p.typeAnnotation)
+      assert.deepEqual(p.typeAnnotation, { kind: 'var', name: 'trans' })
+    })
+  })
 })
 
 describe('enterDecl', () => {
diff --git a/quint/test/ir/IRVisitor.test.ts b/quint/test/ir/IRVisitor.test.ts
index c3c41d5a3..6c9da5333 100644
--- a/quint/test/ir/IRVisitor.test.ts
+++ b/quint/test/ir/IRVisitor.test.ts
@@ -902,5 +902,25 @@ describe('walkModule', () => {
       assert.deepEqual(visitor.entered.map(typeToString), expectedTypes)
       assert.deepEqual(visitor.exited.map(typeToString), expectedTypes)
     })
+
+    it('finds paramater type annotations', () => {
+      class TestVisitor implements IRVisitor {
+        typesVisited: QuintType[] = []
+        exitType(t: QuintType) {
+          this.typesVisited.push(t)
+        }
+      }
+
+      const visitor = new TestVisitor()
+
+      const m = buildModuleWithDecls(['def foo(x: int, b: str): bool = true'])
+      walkModule(visitor, m)
+      const actualTypes = visitor.typesVisited.map(typeToString)
+      // `int` and `str` should each show up TWICE:
+      // - once from of the lambda type annotations
+      // - once from of the parameter type annotation
+      const expectedTypes = ['int', 'str', 'bool', '(int, str) => bool', 'int', 'str']
+      assert.deepEqual(actualTypes, expectedTypes)
+    })
   })
 })