The following is a fairly free translation in verse.

The land of my fathers is dear unto me,
Old land where the minstrels are honoured and free:
Its warring defenders, so gallant and brave,
For freedom their life's blood they gave

Land!,Land!,True I am to my land!

While seas secure,

this land so pure,

o may our old language endure.

O land of the mountains, the bard's paradise,
Whose precipice, valleys lone as the skies,
Green murmuring forest, far echoing flood
Fire the fancy and quicken the blood

For tho' the fierce foeman has ravaged your realm,
The old speech of Wales he cannot o'erwhelm,
Our passionate poets to silence command
Or banish the harp from your strand.

A more literal translation is:

The old land of my fathers is dear to me,
Land of poets and singers, famous men of renown;
Her brave warriors, very splendid patriots,
For freedom shed their blood.

Nation [or country], Nation, I am true to my Nation.

While the sea [is] a wall to the pure, most loved land,

O may the old language [sc. Cymraeg] endure.

Old mountainous Wales, paradise of the bard,
Every valley, every cliff, to me is beautiful.
Through patriotic feeling, so charming is the murmur
Of her brooks, rivers, to me.

If the enemy oppresses my land under his foot,
The old language of the Welsh is as alive as ever.
The muse is not hindered by the hideous hand of treason,
Nor [is] the melodious harp of my country.

Other translations include:

The land of my fathers is dear to me,
Old land where the minstrels are honoured and free;
Its warring defenders so gallant and brave,
For freedom their life's blood they gave.

Home, home, true am I to home,

While seas secure the land so pure,

O may the old language endure.

Old land of the mountains, the Eden of bards,
Each gorge and each valley a loveliness guards;
Through love of my country, charmed voices will be
Its streams, and its rivers, to me.

Though foemen have trampled my land 'neath their feet,
The language of Cambria still knows no retreat;
The muse is not vanquished by traitor's fell hand,
Nor silenced the harp of my land.

and:

The land of my fathers, the land of my choice,
The land in which poets and minstrels rejoice;
The land whose stern warriors were true to the core,
While bleeding for freedom of yore.

Wales! Wales! fav'rite land of Wales!

While sea her wall, may naught befall

To mar the old language of Wales.

Old mountainous Cambria, the Eden of bards,
Each hill and each valley, excite my regards;
To the ears of her patriots how charming still seems
The music that flows in her streams.

My country tho' crushed by a hostile array,
The language of Cambria lives out to this day;
The muse has eluded the traitors' foul knives,
The harp of my country survives.