diff --git a/src/__tests__/components/TransferAdminModal.test.tsx b/src/__tests__/components/TransferAdminModal.test.tsx
new file mode 100644
index 00000000..ad294ea5
--- /dev/null
+++ b/src/__tests__/components/TransferAdminModal.test.tsx
@@ -0,0 +1,69 @@
+import { render, screen, fireEvent } from "@testing-library/react";
+import { StrKey } from "@stellar/stellar-sdk";
+import TransferAdminModal from "@/components/TransferAdminModal";
+
+// The modal reads a few labels from the "Admin" namespace; everything else
+// arrives via props. Mirror the real translations so assertions read naturally.
+jest.mock("next-intl", () => ({
+  useTranslations: () => (key: string) => {
+    const map: Record<string, string> = {
+      requiredWord: "CONFIRM",
+      invalidAddress: "Invalid address",
+      newAdminAddress: "New Admin Address",
+      transferring: "Transferring…",
+    };
+    return map[key] ?? key;
+  },
+}));
+
+// A guaranteed well-formed Stellar public key (correct prefix, length, checksum).
+const VALID_ADDRESS = StrKey.encodeEd25519PublicKey(Buffer.alloc(32, 7));
+const INVALID_ADDRESS = "GNOTAREALSTELLARADDRESS";
+
+const baseProps = {
+  isOpen: true,
+  isTransferring: false,
+  onClose: jest.fn(),
+  title: "Transfer admin",
+  body: "Confirm the transfer.",
+  confirmLabel: "Type CONFIRM to proceed",
+  typeConfirmPlaceholder: "CONFIRM",
+  cancelLabel: "Cancel",
+  confirmButtonLabel: "Transfer",
+};
+
+describe("TransferAdminModal address validation", () => {
+  it("accepts a valid Stellar public key: no error, submit enabled after typing CONFIRM", () => {
+    const onConfirm = jest.fn();
+    render(
+      <TransferAdminModal {...baseProps} onConfirm={onConfirm} newAdminAddress={VALID_ADDRESS} />,
+    );
+
+    expect(screen.queryByText("Invalid address")).not.toBeInTheDocument();
+
+    const confirmButton = screen.getByRole("button", { name: "Transfer" });
+    expect(confirmButton).toBeDisabled();
+
+    fireEvent.change(screen.getByPlaceholderText("CONFIRM"), { target: { value: "CONFIRM" } });
+    expect(confirmButton).toBeEnabled();
+
+    fireEvent.click(confirmButton);
+    expect(onConfirm).toHaveBeenCalledTimes(1);
+  });
+
+  it("rejects an invalid address: shows an inline error and keeps submit disabled", () => {
+    const onConfirm = jest.fn();
+    render(
+      <TransferAdminModal {...baseProps} onConfirm={onConfirm} newAdminAddress={INVALID_ADDRESS} />,
+    );
+
+    expect(screen.getByRole("alert")).toHaveTextContent("Invalid address");
+
+    const confirmButton = screen.getByRole("button", { name: "Transfer" });
+    fireEvent.change(screen.getByPlaceholderText("CONFIRM"), { target: { value: "CONFIRM" } });
+    expect(confirmButton).toBeDisabled();
+
+    fireEvent.click(confirmButton);
+    expect(onConfirm).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/__tests__/unit/validators.test.ts b/src/__tests__/unit/validators.test.ts
index 472c9bea..6cea0744 100644
--- a/src/__tests__/unit/validators.test.ts
+++ b/src/__tests__/unit/validators.test.ts
@@ -1,5 +1,7 @@
+import { StrKey } from "@stellar/stellar-sdk";
 import {
   validateStellarAddress,
+  isValidStellarPublicKey,
   validateAmount,
   validateFundingGoal,
   validateDuration,
@@ -19,6 +21,19 @@ describe("Validators", () => {
     expect(() => validateStellarAddress("G" + "A".repeat(55))).not.toThrow();
   });
 
+  it("isValidStellarPublicKey", () => {
+    const valid = StrKey.encodeEd25519PublicKey(Buffer.alloc(32, 7));
+    expect(isValidStellarPublicKey(valid)).toBe(true);
+    // Tolerates surrounding whitespace from copy/paste.
+    expect(isValidStellarPublicKey(`  ${valid}  `)).toBe(true);
+
+    // Wrong prefix, too short, bad checksum, and empty all fail.
+    expect(isValidStellarPublicKey("")).toBe(false);
+    expect(isValidStellarPublicKey("GABC")).toBe(false);
+    expect(isValidStellarPublicKey("G" + "A".repeat(55))).toBe(false);
+    expect(isValidStellarPublicKey("MNOTAVALIDADDRESS")).toBe(false);
+  });
+
   it("validateAmount", () => {
     expect(() => validateAmount(0)).toThrow(
       new ContractErrorException(ContractError.ContributionMustBePositive),
diff --git a/src/components/TransferAdminModal.tsx b/src/components/TransferAdminModal.tsx
index 5037bd73..b2a24cde 100644
--- a/src/components/TransferAdminModal.tsx
+++ b/src/components/TransferAdminModal.tsx
@@ -2,6 +2,7 @@
 
 import { useEffect, useRef, useState } from "react";
 import { useTranslations } from "next-intl";
+import { isValidStellarPublicKey } from "@/utils/validators";
 
 interface TransferAdminModalProps {
   newAdminAddress?: string;
@@ -44,7 +45,11 @@ export default function TransferAdminModal({
   const [confirmInput, setConfirmInput] = useState("");
 
   const requiredWord = t("requiredWord");
-  const canConfirm = confirmInput.trim() === requiredWord;
+  // When an address is supplied, it must be a well-formed Stellar public key
+  // before submit is allowed. This catches invalid input client-side instead of
+  // failing only after a Freighter signature prompt and a wasted transaction.
+  const isAddressValid = !newAdminAddress || isValidStellarPublicKey(newAdminAddress);
+  const canConfirm = confirmInput.trim() === requiredWord && isAddressValid;
 
   // Reset input and focus when modal opens
   useEffect(() => {
@@ -114,6 +119,11 @@ export default function TransferAdminModal({
             </p>
           </div>
         ) : null}
+        {newAdminAddress && !isAddressValid ? (
+          <p role="alert" className="text-sm font-medium text-red-600 dark:text-red-400">
+            {t("invalidAddress")}
+          </p>
+        ) : null}
         <div>
           <label
             htmlFor="confirm-input"
diff --git a/src/utils/validators.ts b/src/utils/validators.ts
index bc51ea9e..235b5328 100644
--- a/src/utils/validators.ts
+++ b/src/utils/validators.ts
@@ -1,3 +1,4 @@
+import { StrKey } from "@stellar/stellar-sdk";
 import { ContractError, ContractErrorException } from "./contractErrors";
 
 export function validateStellarAddress(
@@ -9,6 +10,18 @@ export function validateStellarAddress(
   }
 }
 
+/**
+ * Non-throwing check that `address` is a syntactically valid Stellar ed25519
+ * public key — starts with `G`, has the correct length, and a valid StrKey
+ * checksum. Intended for client-side form validation where an inline error is
+ * shown rather than an exception thrown (see TransferAdminModal). Unlike
+ * {@link validateStellarAddress}, this verifies the checksum, not just the
+ * length and prefix.
+ */
+export function isValidStellarPublicKey(address: string): boolean {
+  return typeof address === "string" && StrKey.isValidEd25519PublicKey(address.trim());
+}
+
 export function validateAmount(amount: number | bigint): void {
   if (Number(amount) <= 0) {
     throw new ContractErrorException(ContractError.ContributionMustBePositive);